Hydroginástica: Physiological Aspects

• Hidroginástica study notes by Profª. Dra. Cristine Alberton of LabNeuro

Physiological Aspects of Immersion and Aquatic Exercises

• Immersing the human body in a liquid medium exposes it to hydrostatic pressure, different viscosity, and new thermal conditions
• Reflex stimuli during immersion can alter cardiovascular responses during exercise and rest

Immersion and Venous Return

• Immersion increases venous return

Hydrostatic Pressure

• Hydrostatic pressure facilitates blood return
• 1 atm is approximately 760 mmHg, while 1m of water is 73.6 mmHg
• Greater depth increases action

Thermal Conductivity

• Heat exchange is easier between body and water
• Mechanisms for body heat loss differ from land

Pressure Gradient

• Pressure gradient redirects blood from lower limbs to the central-superior body region

Cardiovascular Adjustments

• Return Volume (RV) increases
• Central region circulation increases
• Approximately 180-247ml of blood occurs in the heart
• Hypervolemia occurs

Consequences of Cardiovascular Adjustments

• Ventricular Diastolic Volume (VDF) increases
• Ventricular Systolic (VS) increases via the Frank-Starling mechanism
• Cardiac Output (DC) increases
• Compensatory Heart Rate (FC) decreases

Neuroendocrine Adjustments

• RV increases and stretches the atria, stimulating cardiac receptors
• Secretion of Atrial Natriuretic Peptide (ANP) increases
• Sympathetic activity decreases

Further Consequences of Neuroendocrine Adjustments

• Antidiuretic Hormone (ADH) secretion decreases
• Diuresis and natriuresis increase
• Systemic vascular resistance decreases
• Blood Pressure (PA) decreases

Exercise Prescription Implications

• Alterations occur at rest and during exercise
• Blood Pressure decreases
• FC decreases

Heart Rate Reduction Magnitude at Rest

• Study included 60 healthy women, aged 24 ± 2.5 years
• Measurements taken in standing position on land and during immersion to the xiphoid process for 5 minutes
• Immersion in water leads to a decrease of approximately 18 bpm

Factors Influencing Heart Rate Magnitude

• Water temperature
• Immersion depth
• Initial heart rate
• Body position

Water Temperature's Impact on Heart Rate

• Study involved men immersed at different water temperatures

• Participants rested for 2 minutes

• Water temperature was 33, 30 and 27°C and submerged between the xiphoid process and shoulders

• Reduction in heart rate corresponds w/ the difference between the heart rate on land vs water

• Study showed an inverse proportional relationship between temperature and Heart Rate (HR) reduction

Findings from other studies on temperature and heart rate

• Temperature >= 36°C increases or produces no modification to heart rate in water
• Temperature <= 34°C decreases heart rate in water
• Very low temperatures (14°C) increases heart rate in water

Immersion Depth and Heart Rate

• Study examined heart rate with different levels of water immersion

• The 395 subjects (male and female), ages 7-75 were selected from a group that was healthy, not medicated and studied in water with temperatures around 29-30° C.

• Heart rate decreases with increase from hip to chest level

Depth of Immersion's relation to hydrostatic pressure

• Increases in immersion increase hydrostatic pressure, which reduces heart rate response
• Water temperature and body are constant

Initial Heart Rate vs. Heart Rate in Water

• Reduction in Heart Rate (HR) caused by: increased effect on initial heart rate with submerging in water

Heart Rate Influence

• Low heart rate (50-59 bpm) causes an average reduction of 1 bpm
• Elevated heart rate (120-129 bpm) cases a average of 34 bpm reduction

Heart Rate Reduction Magnitude During Exercise

• Research included 20 healthy women of approximately 24 years of age (± 2.5 years)

• Cadence increase: 80 bpm with 10 bpm Incr

• Temperature: 32°C

• Depth: to where the xiphoid process is at

• Decrease of approximately 6-9 bpm

Submaximal Responses

• Decrease of approximately 12-16 bpm

Maximum Test Protocols

• Maximum test protocols include different modalities (vertical), age, and water temperature
• Vertical maximal testing (FCmax) causes a decrease of = -15.3 bpm

Tests at Lactate Threshold (FCLAn) Show:

• FCLAn decrease of = -11.7 bpm

Heart Rate Monitoring Implications

• Terrestrial HRmax, HRreserve or Lactate Thershold can overestimate water intensity

Blood Pressure and Immersion

• Blood pressure magnitude reduction at rest

• Reduction of blood pressure in resting position

• The research included 10 men, ages 22 (± 2) years

• 60 minutes in resting immersion

• Temperatures: 32° C, 20° C e 14° C

• Heart Rate decreases, 15%

• Systolic/Arterial Pressure (PASrep) decreases, 11%

• Diastolic/Arterial Pressure decreases (PAD rep) decreases 12%

Positive therapeutic effects

• Recommended for those with high tension
• Exercise by itself decreases blood pressure

Blood Pressure Mechanism reduction

• Diuresis increases 107% , which is a higher need for fluid
• Renina decreases to 46%
• Aldosterone drops a total of17%

Water Benefits

• For patients with Cardiometabolic disease a decrease in rening angiotensin II is therapeutic.

Aquatic Post-Exercise Hypotension

• Norm X HipT X HipNT: Comparing a stationary bike versus and regular earth cycling

Intensity Effect

• Exercise intensity at is a total of 75% VO2max for 45 min
• 90 min after a session, those who exercised in water experienced greater hypotension in comparison to earth.

Effects

• For those with high blood pressure there is long lasting (HPE) effect w/exercise in water

Implications

• Alleviates effects before exercises

Impact

• Hipertension = 160x95 mmHg
• Reduces blood pressure increase from exercise to an expected max limit(180x105 mmHg)
• HPE greater; summing total effect or reducing effect

Additional Benefits

• Individuals with type 2 diabetes

• Used walking/running in water

• Tempo was 3:2 at 85-90% FCLAn to about 85% FCLAn

• Study included 12 (♂♀) participants w/Diabetes, between 37-63 years of age that were all over weight and had a 90% hx of High Blood Pressure

• Decrease on systems w/high activity w impact to exercise with water

Other benefits

• Includes pain relief

• Pain from water immersion is diminished; greater sensation can occur

• Water temp and turbulence affect the pain levels

• Water makes it easier as well

• Good for those w/chronic pain

Biomechanical considerations of exercises in water

• There is apparent weight
• Apparent Weight = Weight - Buoyancy

How Depth Impacts Apparent Weight

• At neck level the weight is 92% as Harrison and buildsteroid stated
• at 47% with the quadril effect by various
• 2% by the Tornozelo (ankle)

How Body type impacts apparent weight

• Population that is younger is 69% of kural
• In with older population it’s found to be a 79.5%
• In obese populations the percentage shows a 81%
• In populations in gestation it is around 83%

How water exercises affect apparent weight

• Workout intensity should be prescribed
• Take into account segments that may float
• Those of different heights can impact impact how prescription is needed
• The load bearing or impacts
• Force of reaction of the surface or force of a solid (FRS)
• Can be defined as how surface provides movement = apply act and react

Additional

• Water environment has a force; Fz, Fx e Fy

The Vertical Water Force

• Water depth at chest can occur during Cadence LV1 or LV2
• During Cadence the intensity rises as well

Horizon water force

• Happens from cadences LV1 or LV2
• Depth the xiphoid process allows an increase

Water Displacement impact

• Water changes the direction of force that includes VERTICAL and HORIZONTAL movement in relation to impact

Horizontal Force in water

• Water has variable data but graph 1. shows the Vertical parts in the environment

High water influence factors

• Factors vary from women at given Cadence rates 90, 110 e 130 bpm

Velocity impact with water

• Velocity = Fz

Impacts from Water studies.

• Used 10 women of high body fat levels in the process area/ xifoide process in test
• Found the aquatic therapeutic benefits help joint
• Impact force on water varies,

Additional water influences

• The exercises depends variable depth for different styles
• At a greater deep depth there will be diff intensity ==End of generated study notes==