Automated Fitness Level (VO2max) Estimation with Heart Rate and Speed Data PDF

Automated Fitness Level (VO2max) Estimation with Heart Rate and Speed Data Firstbeat Technologies Ltd. This white paper has been produced to review the method and em...

Automated Fitness Level (VO2max) Estimation with Heart Rate and Speed Data Firstbeat Technologies Ltd. This white paper has been produced to review the method and empirical results related to the heart rate variability and speed based VO2max estimation method from any freely performed workout developed by Firstbeat Technologies Ltd. Parts of this paper may have been published elsewhere and are referred to in this document. TABLE OF CONTENTS IMPORTANCE OF AEROBIC FITNESS (VO2MAX)..................... 1 Aerobic fitness is related to a person’s ability to perform Introduction........................................................................ 1 dynamic, moderate-to-high intensity physical activity with large Aerobic fitness, health, and quality of life........................... 2 muscle groups for prolonged periods. Thus, it expresses the Aerobic fitness and physical work capacity......................... 2 abilities of both cardiorespiratory and muscular systems to Aerobic fitness and sports performance............................. 2 transport and utilize oxygen for energy. It is one of the most Methods used to estimate aerobic fitness.......................... 2 fundamental measures of human physiology with remarkable DESCRIPTION OF THE FIRSTBEAT METHOD........................... 3 health, wellbeing, life quality, work ability, and performance - Physiological basis of the method....................................... 3 related associations [1-5]. Calculation steps................................................................. 3 Only reliable data used for VO2max estimation.................. 3 Typically VO2max is measured directly by analyzing inspired and VALIDATION OF THE FIRSTBEAT MODEL............................... 4 expired breathing gases in a laboratory setting during maximal COMPARISON OF DIFFERENT FITNESS TESTS........................ 5 exertion, and expressed either as absolute maximal amount of PRACTICAL USE OF THE FIRSTBEAT METHOD........................ 5 oxygen per minute (L/min) or as relative to the individual’s Assessing fitness level for health and work ability.............. 5 weight as the maximal milliliters of oxygen the person uses in Improving VO2max by training............................................ 6 one minute per kilogram of body weight (ml/kg/min). Assessing competitive sports performance and training.... 7 CONCLUSIONS...................................................................... 8 In addition to oxygen consumption (VO2), the energy cost of REFERENCES......................................................................... 8 physical activities can be expressed as metabolic equivalents (MET; Metabolic Equivalent of Task). MET is defined as the ratio SUMMARY of metabolic rate (and therefore, the rate of energy consumption) during a specific physical activity to a resting A person’s maximal oxygen uptake (VO2max) refers to the metabolic rate. One MET is defined as 1 kcal/kg/hour or 3.5 maximal amount of oxygen the individual can consume ml/kg/min, and it is roughly equivalent to the energy cost of typically over one minute during an intense physical effort sitting quietly. VO2max is the golden standard measure for the person’s aerobic fitness level Individual VO2max values can range from about 10 ml/kg/min in Aerobic fitness level is strongly and positively related to cardiac patients to close to 90 ml/kg/min among world-class health, longevity, quality of life, and performance endurance athletes. Average values for men and women in Aerobic fitness level is typically measured either directly in a different age groups have been used to establish reference laboratory from breathing gas exchange, not viable for real- fitness categories, as aerobic fitness generally declines with age life use, or indirectly with controlled exercise protocols [1, 6]. The present white paper describes a method for assessing a person’s aerobic fitness level (VO2max) automatically from It would be extremely beneficial to measure VO2max accurately any freely performed, uncontrolled exercise in real-life because laboratory tests are typically directed The method is based on the well-known heart rate vs. speed towards special subject groups, such as persons with known or relationship and on detecting the most reliable data periods suspected cardiovascular diseases or high-level athletes. In for VO2max estimate during the exercise addition, laboratory tests require expensive equipment and trained personnel, and are thus difficult and expensive to IMPORTANCE OF AEROBIC FITNESS (VO2MAX) perform. Therefore, they are not feasible for large-scale use and Introduction do not allow for frequent follow-up of aerobic fitness. Maximal oxygen uptake or consumption (VO2max) means the Consequently, there would be several valuable application areas maximal capacity of an individual to perform aerobic work. It is for accurate real-life fitness level information. The information the product of cardiac output (CO) and arteriovenous oxygen could be used for example for assessing the current fitness level (AV-O2) difference at exhaustion, and the golden standard in different populations, motivating towards physical activity, measure for a person’s aerobic fitness. It refers to the giving feedback on specific exercise sessions or long-term maximal amount of oxygen the individual can utilize typically progress, helping to choose suitable exercise modes, and even in over one minute during an intense, maximal effort. planning entire training programs. Automated Fitness Level (VO2max) Estimation with Heart Rate and Speed Data © 2014 Firstbeat Technologies Published: 07/11/2014, updated: 30/06/2017 All rights reserved  2 The present white paper describes a method for estimating exercise above 100% of VO2max for extended periods. Oxygen VO2max from any freely performed, uncontrolled real-life delivery to exercising muscles is viewed as the primary limiting exercise developed by Firstbeat Technologies Ltd. The method factor for VO2max. In addition, the ability to exercise at a high is based on utilizing the most representative and reliable data intensity level for prolonged periods (e.g. distance running) is on the individual’s heart rate and speed during exercise. The determined by fat oxidation, ability to buffer lactic acid, method provides an accurate, yet easy way to monitor the economy of performance, and fractional utilization of VO 2max progress in aerobic fitness level on a daily basis in real-life for the given speed [5, 12]. Table 1 expresses examples of settings. oxygen consumption requirements of different tasks. Aerobic fitness, health, and quality of life Table 1. Examples of oxygen consumption requirements during different tasks and activities. The higher the requirement, the better the individual’s aerobic fitness level needs to be to be Low level of aerobic fitness is an inevitable consequence of able to perform the task. Thus, VO2max is used to describe the physical inactivity and sedentary lifestyle that some experts individual’s functional capacity. 1 MET ≈ 3.5ml/kg/min. state to be the most important public health problem of the 21st century. Physical inactivity and poor physical fitness are Tasks, activities, and METs VO2 associated with several health problems, such as cardiovascular occupations required (ml/kg/min) diseases, metabolic disorders (e.g. overweight, obesity, required diabetes), musculoskeletal disorders, pulmonary diseases, Sleeping 0.92 3 cancer, psychological problems and so on [e.g. 2-3]. Inactivity (sitting quietly, 1.0 4 watching TV etc.) Consequently, low levels of aerobic fitness have also been Office work (computer) 1.6 6 associated with a markedly increased risk of premature death Car driving 2 7 [8-9]. Positively, improvements in aerobic fitness have been Light housework (dishes) 2.1 7 shown to reduce all-cause mortality [9-10]. Furthermore, Healthcare support (nursing) 2.8 10 although aerobic fitness generally declines with age, by belonging to a higher fitness category, one can better maintain Walking 5km/h 3.2 11 functional ability with aging or during retirement. In Heavy housework (washing 3.3 12 practical terms, for a person with poor fitness level, a 10% floors) Gardening (digging) 4.4 15 increase in VO2max can reduce mortality risk by 15% and give 10 more years of good-quality life. Fishing 4.5 16 Walking upstairs 4.7 16 Aerobic fitness and physical work capacity Walking 7km/h 5.3 19 Cycling 20km/h 7.1 25 Aerobic fitness i.e. the cardiorespiratory capacity is also related Backpacking 6.4km/h, 5% 8 28 to an individual’s ability to cope with the demands of work. This slope, 20kg is especially important when considering the changing Running 9km/h 8.8 31 demographics and as the retirement age is getting higher, along Cycling 30km/h 9.8 34 with longer life expectancy. Based on international Ice hockey (competitive) 10 36 recommendations, work should not demand more than 50% of Firefighting (standard fire 11.9 42 a person’s VO2max. However, the level of physical abilities suppression tasks while required to sufficiently perform job tasks may vary from wearing personal protective minimal to extreme between different jobs. Therefore, equipment) especially in physical work, aerobic fitness level is a crucial Running 15km/h 14.6 51 factor regarding the individual’s ability to perform the needed Running 19.3km/h 19 67 tasks. This leads to a conclusion that the demands of work Running 22.5km/h 23 81 should be reduced along with a decreased physical fitness level (typically occurring with increasing age) and/or the aerobic Methods used to estimate aerobic fitness fitness level needs to be maintained or improved through physical activity if the person aims to meet the work The only direct way to actually measure maximal oxygen requirements. consumption is to use open-circuit spirometry in a laboratory. In this procedure, pulmonary ventilation and expired fractions of Aerobic fitness and sports performance oxygen and carbon dioxide are measured during a controlled exercise protocol. When the direct measurement of VO 2max is In addition to its effect on health and work ability, maximal not feasible or desirable, a variety of submaximal or maximal oxygen uptake is a crucial determinant of endurance indirect tests with a controlled exercise protocol can be used to performance [e.g. 5, 12]. VO2max sets the upper limit for estimate VO2max. Also, non-exercise methods have been metabolism during physical activity because it is impossible to developed to estimate a person's VO2max from individual Automated Fitness Level (VO2max) Estimation with Heart Rate and Speed Data © 2014 Firstbeat Technologies Published: 07/11/2014, updated 30/06/2017 All rights reserved  3 characteristics such as age, sex, anthropometrics, history of Calculation steps physical activity, or resting-level physiological measurements. However, these non-exercise based assessment methods The following calculation steps are used for VO2max estimation: are often very inaccurate. 1) The personal background info (at least age) is logged 2) The person starts to exercise with a device that measures heart rate and speed DESCRIPTION OF THE FIRSTBEAT METHOD 3) The collected data is segmented to different heart rate ranges and the reliability of different data segments is The Firstbeat method for accurate assessment of a person’s calculated aerobic fitness level (VO2max) during uncontrolled exercise is 4) The most reliable data segments are used for estimating the described next in detail. person's aerobic fitness level (VO2max) by utilizing either linear or nonlinear dependency between the person's heart Physiological basis of the method rate and speed data. It is well known that there is a linear relationship between Only reliable data used for VO2max estimation oxygen consumption and running speed. The oxygen cost of running increases when running speed increases. At identical One of the key features of this method is the detection of submaximal speeds, an endurance athlete runs at a lower reliable periods for VO2max detection. Figure 1 shows an percentage of his or her VO2max than an untrained person, example of how fitness level can be reliably detected during an although both maintain similar VO2. uncontrolled running session. The reliability detection includes both exercise mode detection and data reliability detection. Technology (such as GPS sensors and foot pods in wrist devices There are some situations in which the exclusion of data or mobile phones) enables reliable measurement of running segments is necessary for reliable fitness level estimation. These speed along with heart rate (HR). Therefore, these parameters automatically detected situations are, for example, running on can be monitored continuously and automatically during each soft ground, on a steep downhill, stopping at a traffic light workout. Because VO2max is a key variable to fitness training (where the speed is zero but the heart rate is elevated), or the that needs to be easily measurable without additional effect of cardiovascular drift (heart rate elevation) in long- protocols, an automatic VO2max estimation method applicable duration workouts. for any uncontrolled workout has been developed by Firstbeat. The method is based on the well-known connection between Figure 2 (next page) further illustrates the difference between heart rate and the speed of the activity (e.g. running, walking). traditional fitness tests in a laboratory that need fixed exercise protocols and the Firstbeat VO2max method based on the data from uncontrolled real-life exercise. Figure 1. Reliable detection of fitness level during uncontrolled running exercise (Firstbeat patented technology). Automated Fitness Level (VO2max) Estimation with Heart Rate and Speed Data © 2014 Firstbeat Technologies Published: 07/11/2014, updated 30/06/2017 All rights reserved  4 Figure 2. Comparison of the VO2max testing concept between traditional laboratory assessments (on the left) and Firstbeat real-life VO2max assessment (on the right). VALIDATION OF THE FIRSTBEAT MODEL into 4.3% when real HRmax was used. The repeatability of the test was good, and the method was suitable for different The Firstbeat VO2max method has been developed against running conditions. laboratory measured VO2max values (Figure 3) and validated with different exercise modes. The accuracy of the method when applied for running is 95% (Mean absolute percentage error, MAPE ~5%), based on a database of 2690 freely performed runs from 79 runners whose VO2max was tested four times during their 6-9 -month preparation period for a marathon. In a vast majority of the measurements, the error was below 3.5 ml/kg/min and the error was evenly distributed around the mean value. For perspective, the error in a typical indirect submaximal test is 10-15% and in a direct laboratory test about 5%. As shown in Figure 4, the estimation error falls close to 5% in running already with a very short period of data, and in 75% of Figure 3. The Firstbeat method has been developed against the workouts, VO2max has been assessed successfully after measured VO2max values in laboratory tests. running 2 kilometers. The method has been validated also with freely performed cycling by 29 cyclists whose pedaling power and heart rate were collected. The accuracy of the method when applied for cycling was 92% (MAPE ~5%). Additionally, data from 42 freely performed walking by 32 persons with various fitness levels has been collected and compared to direct laboratory test data. The results showed that when applied for walking, the MAPE was ~6%. Because the Firstbeat method is sub-maximal by nature, it uses an age-based estimated maximum heart rate (HRmax) in the calculation. Therefore, the error in the HRmax estimation Figure 4. Mean absolute percentage error (MAPE) for VO2max affects the accuracy of the VO2max estimate. Figure 5 shows estimate of the Firstbeat method (upper), and the percentage of how many (%) of the 2690 workouts were successfully given how much the difference between a person's actual and age- a VO2max estimate relative to running distance (lower). based HRmax affects the VO2max estimation error in the mentioned database of 2690 freely performed workouts. If the HRmax is estimated 15 beats/min too low, the error in the VO2max result is about 9%. Respectively, if the HRmax is estimated 15 beats/min too high, the error in VO 2max result is 7%. If the person's real HRmax is known, the VO2max assessment error falls to the 5% level. A study examining the accuracy and replicability of results by the Firstbeat method (used foot pod to measure running speed and laboratory tests for reference) found that the method Figure 5. Error (%) in VO2max estimation relative to the error in slightly underestimates the true VO2max but the %-error fell age-based maximal HR estimation. Automated Fitness Level (VO2max) Estimation with Heart Rate and Speed Data © 2014 Firstbeat Technologies Published: 07/11/2014, updated 30/06/2017 All rights reserved  5 COMPARISON OF DIFFERENT FITNESS TESTS monitor physical and functional capacity and the changes in them. In addition, VO2max information can be used, for A variety of methods have been developed to assess VO2max from example, to guide nutritional interventions or exercise training submaximal or maximal exercise. These methods are based programs to achieve the individual’s goals and targets, such as mostly on the linear relationship between oxygen uptake (VO2) improved endurance, changed body composition, or better and power output, as well as between VO2 and heart rate during quality of life. exercise. VO2 tests have most often been conducted on a cycle ergometer, a treadmill or a rowing ergometer. As described, VO2max can be expressed as ml/kg/min, but that value can be confusing for persons unfamiliar with the topic. Non-exercise estimates of VO2max have also been used, and Therefore, VO2max is typically expressed as individual fitness those have been based for example on the ratio between HRmax level relative to the reference group of the same age and and HRrest, or on self-reported predictor variables, such as gender. Tables 3a and 3b (next page) show fitness level subject’s perceived functional ability to exercise, habitual categories based on VO2max values in different age groups for physical activity, age, gender, body mass, body mass index, and both genders. body composition (% of fat). All of the methods have some advantages as well as limitations, which are summarized in Table In general, the highest VO2max values are reached around the 2. age of 20, after which the aerobic fitness starts to decline. Moreover, men have about 20% higher values than women due to differences in body size, body composition and blood volume PRACTICAL USE OF THE FIRSTBEAT METHOD. The current scientific evidence supports the view of 10% decline per decade in VO2max among both men and women, Next, more details about the key practical use cases of the regardless of activity level [11, 15-16], although some studies Firstbeat VO2max method are presented. have found that the VO2max of active individuals declines at a slower rate than that of inactive persons. A possible Assessing fitness level for health and work ability explanation is that changes in VO2max over the entire age range may be curvilinear, with active individuals declining slowly as VO2max can be used to indicate general cardiorespiratory long as they keep exercising, and inactive individuals declining health but also to monitor the progress of fitness with different at a rapid rate during their 20's and 30's, followed by a slower training protocols. As aerobic fitness level is strongly associated rate of decline of their VO2max as they age further [15,17]. Still, with health and ability to perform daily tasks, it can be used to to be able to perform daily tasks and maintain functional ability also at an older age, it would be extremely important for everyone to aim for a sufficient aerobic fitness level. Table 2. Methods used to measure or estimate fitness level. Fitness test Accuracy Advantages Limitations Exercise-based tests Expensive. Maximal effort required so suitable for healthy The golden standard method as the The most accurate test for aerobic fitness and persons only (difficult for specific populations). Direct VO2max laboratory only test that truely measures can also be used to estimate anaerobic Interpretation of results requires a specialist. Motivation to test (gas analysis) maximal oxygen consumption threshold. "reach the individual limits" can have significant impact on the results. Works on freely performed everyday Exercising conditions should be standardized to get reliable Firstbeat VO2max Correlation between estimated and exercise without a need for separate test. results. For example running surface and wind may have real-life estimation measured V02max 0.95. MAPE 5%. Cheap and very easy to perform. Does not effect on the result. require maximal effort. Indirect submaximal Not as accurate as direct test but can Cheaper and safer than direct test allowing Requires fixed and controlled protocol. Accuracy of the test (treadmill, cycle ergometer, be more accurate than Cooper's-test usage for larger populations. Duration usually is dependent on accuracy of maximal heart rate estimation step test) and walking tests shorter and no maximal effort required. Can be used in field conditions. Easy to Requires maximal effort. For fit and healthy persons only. HR Cooper's 12-min test / 1.5- Quite accurate administer to large numbers of individuals at usually not monitored. Motivation and pacing can have an mile test and others the same time. impact on results. Walking tests Able to estimate changes in fitness Can be used in field conditions. Easy to Fitness level of very fit persons may be underestimated. (e.g. UKK 2 km test / level. The least accurate from administer to large numbers of individuals at Motivation and pacing can have an impact on results. Rockport 1 mile test) exercise tests presented the same time. Safe. Distance has to be measured accurately. Non-exercise tests Simple and safe. No exercise required. Easy Non-exercise equations Not as accurate as an exercise based to administer to large numbers of individuals Heavily based on self-chosen activity level. (e.g. Jackson et al 1990 etc.) tests. at the same time. Very inaccurate if only resting heart Resting heart rate test Does not require exercise. Does not have solid physiological basis rate used Automated Fitness Level (VO2max) Estimation with Heart Rate and Speed Data © 2014 Firstbeat Technologies Published: 07/11/2014, updated 30/06/2017 All rights reserved  6 Table 3a. Fitness level (VO2max) classification for men [Adapted from 33]. Age (year) Very poor Poor Fair Good Excellent Superior from to under from to from to from to from to over 20 29 36.7 38.0 41.0 41.7 44.8 45.6 48.5 51.1 54.0 55.5 30 39 35.2 36.7 39.5 40.7 43.9 44.1 47.0 48.3 51.7 54.1 40 49 33.8 34.8 37.6 38.4 41.0 42.4 44.9 46.4 49.6 52.5 50 59 30.9 32.0 34.8 35.5 38.1 39.0 41.8 43.3 46.8 49.0 60 69 27.3 28.7 31.6 32.3 34.9 35.6 38.3 39.6 42.7 45.7 70 79 24.6 25.7 28.4 29.4 31.6 32.4 35.2 36.7 39.5 43.9 Table 3b. Fitness level (VO2max) classification for women [Adapted from 33]. Age (year) Very poor Poor Fair Good Excellent Superior from to under from to from to from to from to over 20 29 30.9 32.3 35.2 36.1 38.5 39.5 42.4 43.9 46.8 49.6 30 39 29.4 30.9 33.8 34.2 36.9 37.7 41.0 42.4 45.3 47.4 40 49 28.2 29.4 32.3 32.8 35.2 35.9 38.6 39.6 43.1 45.3 50 59 25.8 26.8 29.4 29.9 32.3 32.6 35.2 36.7 38.8 41.0 60 69 23.9 24.6 26.6 27.3 29.4 29.7 32.3 32.7 35.9 37.8 70 79 22.2 23.5 25.3 25.9 28.0 28.1 29.8 30.6 32.5 37.2 Regarding the health effects of VO2max, an interesting meta- mass index change. A recent meta-analysis concluded that analysis of 23 studies, examining the effect of leisure-time there is more and more evidence to suggest that aerobic fitness physical activity and fitness level on the risk for coronary heart modifies the association between adiposity and mortality. disease (CHD) and/or cardiovascular disease (CVD) was In the general population, better aerobic fitness is associated conducted. The study found that the disease risk was with improvements in obesity-related cardiometabolic risk reduced significantly better by being more physically fit than by factors, resulting in improved survival comparable to fit and being more physically active (Figure 6). Although it is clear that normal-weight individuals and further highlighting the physical fitness can be improved by training, the study importance of fitness level for health. highlights the importance of aerobic fitness level per se as a significant health factor. The reductions in relative risk were In addition to its importance for health, relatively high VO2max nearly twice as great for cardiorespiratory fitness than for is needed in many occupations, especially in physical work, such physical activity. as in some tasks related to firefighting, construction, forestry, manufacturing, farming, transporting, and nursing (see examples of the oxygen demands of different tasks in Table 1). An 8-hour work shift should preferably not demand more than 30-50% of individual VO2max to avoid overloading. Fitness level measurements can be used to indicate individual abilities and tolerable levels. Improving VO2max by training Everyone can improve aerobic fitness by training. The magnitude of the improvement depends substantially on the starting point and the intensity of training. The less fit an individual is when he/she starts exercising, the easier it is to Figure 6. The relative risk for CHD or CVD by being physically increase the VO2max [18-19]. Vigorous exercising seems to be active versus having better physical fitness (risk=1 for the least more effective than moderate exercising for improving VO2max, active or fit) [modified from 27]. and highly fit individuals improve less than less fit at any given training intensity. Moreover, studies have found that better aerobic fitness seems to be cardioprotective also in overweight or obese persons, Indeed, a beginner may increase his/her fitness level during 4- compared to less fit counterparts. Indeed, a longitudinal study 10 weeks of successive training by up to 10-20% [18-19], with 14,345 men found that maintaining or improving aerobic although even 44% increase in VO2max in ten weeks has been fitness over a period of 6.3 years was associated with reported for persons with average aerobic fitness, by using very significantly lower mortality from CVD regardless of the body high-intensity interval training. Still, for highly trained Automated Fitness Level (VO2max) Estimation with Heart Rate and Speed Data © 2014 Firstbeat Technologies Published: 07/11/2014, updated 30/06/2017 All rights reserved  7 athletes who already have a very high VO2max, it is extremely of adaptation. hard to significantly improve aerobic fitness within a short time period. In any case, it is important to monitor VO2max regularly Figure 7 shows how important it is to adjust the training based to see whether the training is effective in improving aerobic on the aerobic fitness level. In the example, a trained person fitness or if some changes in the training program are required. (high VO2max) and untrained person (low VO2max) are A concrete, regular result also motivates to continue training. performing exactly the same exercise sessions (black bars). As a result, the fitness level of the untrained person develops with Assessing competitive sports performance and training training, while the fitness level of the trained person begins to decrease, as the training level is too low for him/her. Thus, knowing the VO2max helps to start training at optimal intensity, Race time prediction and can be used to personalize and plan the training [19, 22]. One of the most interesting application areas for VO2max information is the prediction of race time. In sedentary runners, improvements in VO2max most probably result in improvement in race time, and therefore, the prediction of race time based on VO2max is quite straightforward. In elite endurance athletes, VO2max is not the only determinant of a good race performance, since they all have high VO2max and the margins between the athletes are small. Thus, other physiological, biomechanical, and psychological factors affect the competition results significantly. For example, if a sedentary runner improves his/her VO2max by 2ml/kg/min, the marathon race time could improve an Figure 7. An untrained and trained person’s VO2max astonishing 15min, while the same absolute improvement in development when both have done the same training sessions. VO2max in an elite athlete could improve the marathon race time by only one and a half minutes! In any case, race time If the training load (volume and/or intensity) is too low prediction provides interesting and concrete feedback about compared to a person’s current fitness level, the VO2max will the current fitness level and a rough estimate of the expected not increase and can start to decrease, and if the training load ability to perform in a race. See an example of Jack Daniels’ race is too high, the fitness level can decrease due to overloading. time prediction in Table 4. With an optimal training load, the fitness level development is the greatest. For this reason, fitness level monitoring is an Table 4. Race time prediction based on VO2max. essential part of training and coaching. Figure 8 shows an VO2max Marathon 1/2 Marathon 10K 5K 1Mile example of how periods of different training load (black bars) 30 4:49:17 2:21:04 1:03:46 30:40 9:11 affect the fitness level development in an untrained person. 36 4:10:19 2:01:19 54:44 26:22 7:49 42 3:40:43 1:46:27 48:01 23:09 6:49 48 3:17:29 1:34:53 42:50 20:39 6:03 54 2:58:47 1:25:40 38:42 18:40 5:27 60 2:43:25 1:18:09 35:22 17:03 4:57 66 2:30:36 1:11:56 32:35 15:42 4:33 72 2:19:44 1:06:42 30:16 14:33 4:13 78 2:10:27 1:02:15 28:17 13:35 3:56 84 2:02:24 58:25 26:34 12:45 3:41 Personalized training Optimal exercise intensity is a key factor in successful training. For example, by conducting basic endurance workouts at right intensity increments in training volume and a greater frequency and quality of more intense workouts are enabled. The training Figure 8. Effect of different training load on fitness level intensity that elicits the improvement in VO2max is highly development. An optimal training load results in the best dependent on the initial aerobic fitness level. Therefore, it is progress in aerobic fitness. safer for initially sedentary persons to begin with moderate intensity exercise, which is effective enough to improve their VO2max, and move up to higher intensities only after a period Automated Fitness Level (VO2max) Estimation with Heart Rate and Speed Data © 2014 Firstbeat Technologies Published: 07/11/2014, updated 30/06/2017 All rights reserved  8 Athlete recovery and supercompensation The method utilizes only reliable data periods and has been found to be very accurate. In order to obtain consistent results, Periodization of hard and easy training is the key for successful the exercise conditions should, however, be standardized fitness improvement [e.g. 23-26]. Athletic performance because for example running surface, wind, and high altitude improves as the athlete adapts to progressively increasing may affect the moving speed. When applied in unstandardized training loads and this adaptation occurs during periods of conditions (such as high altitude), the method expresses the recovery and reduced training. High-intensity training for changes in performance in those conditions. longer periods results in a decrease in performance. If there is a reasonable recovery phase after that, the performance will The method makes it possible to evaluate the effectiveness of return to the baseline and further above it. This is called training on a day-to-day basis rather than checking the aerobic supercompensation. fitness level seldom, with separate tests (e.g. once a year). Thus, the Firstbeat VO2max method allows continuous follow-up of If a new exercise session is applied at the peak of the aerobic fitness, and helps to plan and personalize training. supercompensation, this will result in further enhancement in The method can also be used to estimate recovery or performance [23-26]. The time needed for supercompensation supercompensation from the preceding training load, and even and recovery is individual and greatly affected by several to predict race times. internal and external factors, such as training, stress, eating, sleeping, and health status. The real recovery is unknown until the recovery has taken place. The only unquestionable measure REFERENCES of recovery is the change in performance, i.e. whether VO2max is improving or declining in the short and long term. Because the American College of Sports Medicine (2010). ACSM’s Guidelines recovery can vary significantly, it is beneficial to determine the for Exercise Testing and Prescription. Lippincott Williams & Wilkins. 8th edition. body's readiness to exercise by measuring performance. 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