Men vs Women: Physiology & Exercise Design

• Program design differs somewhat for women
• Physical activity levels in the US, measured by accelerometer:
  • Ages 20-29:
    • Males: Moderate = 37.9 min, Vigorous = 1.9 min, Combined = 39.7 min
    • Females: Moderate = 22.4 min, Vigorous = 1.3 min, Combined = 23.6 min
  • Ages 30-39:
    • Males: Moderate = 41.3 min, Vigorous = 1.6 min, Combined = 42.8 min
    • Females: Moderate = 19.9 min, Vigorous = 1.4 min, Combined = 21.3 min
• 185 males, 190 females participated in a 7-day accelerometer assessment

Physiological Differences between Men and Women

• Similar fiber type composition between men and women; men do not have a greater percentage of fast-twitch muscle fibers
• Men have larger muscle fibers, especially fast twitch fibers, slow-twitch fibers are also larger
• Male muscle fibers do not contract more quickly than female muscle fibers; generate force more quickly due to greater size
• Women utilize more fat and less carbs/protein during exercise, men derive more energy from carbs
• Body composition before puberty shows virtually no differences between males and females
• Fat mass vs lean mass is a differentiating factor after puberty
• Absolute Strength: Max amount of force exerted, regardless of body size.
• Women produce about 2/3 the amount of strength, compared to men.
• Men's upper body is much stronger than females, though women are more comparable to men in lower body strength.
• Relative Strength: Amount lifted/force applied relative to an individual's body size.
• Relative oxygen consumption is measured in ml/kg/min
• Absolute oxygen consumption is measured in L/min
• VO2 max is the product of maximal cardiac output and arterial-venous oxygen difference
• VO2 max = Q x a-vO2 diff

Benefits of Exercise for Women

• Benefits are the same for men, except that program design should differ and there is a 12% lower risk of breast cancer.

Testing and Guidelines

• Guidelines are similar for men and women, but program design is different per gender.

Special Considerations for Women in Program Design

• Include the following considerations:
  • Knee injuries
  • Female athlete triad
  • Pregnancy/Post-Partum
  • Menopause
  • Osteoporosis

Knee Injury Risk

• ACL Tears:
  • Higher risk is due to a smaller femoral notch and Q angle differences versus males. -Quad overcompensation: -Leads to excess stress on the knee joint -Q angle stress causes added tension to ligaments -Reduce knee injuries with screenings, year-round conditioning, fitting apparel, and monitoring dietary intake.

Female Athlete Triad

• Refers to three interrelated health issues:
  1. Disordered Eating
  2. Menstrual Dysfunction
  3. Loss
• Early detection of the triad is key
• Observation points
  • Irregular menstruation
  • Fatigue
  • Sleeping disorders
  • Stress fractures
  • Efforts to be thinner etc...
• Long-term consequences of the female athlete triad
  • Malnourishment
  • Dehydration
  • Cognitive dysfunction
  • Stress fractures
  • Osteoporosis
  • Infertility

Terminology

• Menstrual dysfunction:
  • Oligomenorrhea is irregular or less frequent menstruation cycles,
  • Amenorrhea is when three or more menstruation cycles are missed consecutively.
• Eating Disorders:
  • Anorexia Nervosa is characterized by low body weight, obsession of body shape/size, fear of gaining weight, and restrictive eating behaviors.
  • Bulimia Nervosa is characterized by a pattern of binge eating, followed by behaviors to compensate for the overeating (throwing up).
  • Binge Eating involves consuming mass quantities of food, but is not followed by compensatory behaviors.

Pregnancy Considerations

• Pregnancy is marked by weight gain over approximately 36-40 weeks, divided into three trimesters lasting 12-13 weeks each.
• Important time points:
  • Week 11-13: risk of miscarriages
  • Week 22: point of viability
  • Week 38-42 weeks: full term
• Concerns with exercise during pregnancy
  • Blood flow redistribution
  • Hyperthermia
  • Hormone-induced Uterine Contractile Activity via cortisol
  • Fetal Hypoglycemia/low blood sugar in the fetus

Other Considerations for Exercise During Pregnancy

• Terminate exercise for
  • Pre-term labor
  • Decreased fetal movement
  • Vaginal bleeding
  • Amniotic fluid leakage
  • Contraindications
• Wait until 6 weeks post-natal checkup before increasing intensity
• Low-impact exercise is recommended during this time
• Avoid:
  • Contact sports
  • Supine exercises after the first trimester
  • Motionless Standing
  • Valsalva
  • Heat Stress
  • Rapid bouncing
• Guidelines vary based off PA history and body composition

Postpartum Depression (PPD)

• PPD is a depression disorder that begins after childbirth.
• Potential causes:
  • Hormone changes (2 weeks):
    • Estrogen & Progesterone
  • Serotonin: neurotransmitter playing a role in mood
  • Effects of body composition
  • New life demands
• Baby Blues affects 30-75% of mothers, may be mistaken for PPD Symptoms are more intense and longer lasting in PPD cases.
• Postpartum Depression may last 6 weeks to 6 months
• Postpartum psychosis:
  • Onset within days-weeks and is rare but dangerous
  • Involves increased risk of harming themselves or their babies
  • Accompanied by hallucinations and delusions
  • Is treatable via inpatient mental healthcare
• Prevalence
  • 1991- 9.3%
  • 1996- 13%
  • CDC- Today 1 in 8 women experience symptoms of PPD:
    • 8-19% CDC, 6.5-20% NIH
  • 10-15% (2004-2005) Rate of depression diagnoses following delivery is rising, and 7 times higher in 2015
  • 4% of fathers
• Negative outcomes of PPD:
  • Decreased care provided to child
  • Negative parenting behaviors
  • Poor infant-mother bond
  • Negative child development PPD and New Fathers: Postpartum blues especially common three to six months after birth, with as many as one in four dads experiencing symptoms Feeling like a third wheel Provider pressure Guilt Signs: Anger
• Women who should be monitored include: Difficulty getting pregnant Pre-mature labor/delivery Birthing complications Birth Defects. Irritability/mood swings Sleep disorders Fatigue Fear of harming the baby/anxious Reluctance to breastfeed Very controlling or very withdrawn Crying spells
• Exercise can decrease severity of PPD, however more evidence to needed
• Improved Body Composition = improved self-confidence Release of Endorphins Increased Serotonin
• Future Directions:
  • Need more research
  • Studies In Progress:
  • The effectiveness of exercise as a treatment for postnatal depression
  • Telephone based exercise intervention for the prevention of postpartum depression
  • Further examination of Cause and Effect is need

Menopausal Osteoporosis

• Menopause is defined as no menses for 12 months
• Decrease estrogen during this phase
• About 20% bone loss in first 5-7 years after menopause
• Consequences include osteoporosis and fragile bones
• Exercise Recommendations Weight bearing? Medical Clearance BMD Measurement Fitness Assessment Strength Exercises Flexibility Exercises Stability/balance exercises Special Precautions: Look Below Increased strength, improved balance, decreased risk of broken bones, and improved posture are the benefits. High impact exercises and bending and twisting should be avoided.