188 SECTION 3 • MEDICAL PROBLEMS IN THE ATHLETE
- Oxygen capacity decreased with haitus and incr-
eased with retraining. - Ca2+levels decreased with retraining as PTH levels
increased throughout the break and retraining peri-
ods (Klausen et al, 1993).
- One acute bout of prolonged endurance exercise to
exhaustion in well trained individuals increased PTH
levels thus inhibiting bone formation and stimulating
bone resorption (Brahm and Ljunghall, 1996).
•Five hours of endurance exercise at 50% maximum
capacity resulted in increased PTH levels after the first
hour and throughout the remainder of the exercise
(5–7% preexercise levels).
•Ca2+in plasma tended to be low during exercise
(Ljunghall et al, 1986). - Resistance exercise:Strength training consisting of
85% of 3-RM leg press significantly increased PTH
levels (Rong et al, 1997). - Chronic exercise: Well-trained individuals per-
formed one single bout of long-term exhaustive exer-
cise had increased PTH levels thus stimulating bone
resorption and Ca2+ efflux to plasma (Brahm and
Ljunghall, 1996). - Increased PTH levels following a maximal exercise
test were significantly higher in endurance trained
elderly men versus untrained elderly men (Zerath
et al,1997).
OVARIANHORMONES ANDEXERCISE
- Endurance exercise: Progesterone and estradiol
levels taken during graded exercise showed only
small increases in both the follicular and luteal
phase.- Greatest increase with increasing intensities
- LH and FSH did not change; the effects on proges-
terone/estradiol may only be because of increases
in plasma volume (Jurowski, 1978).
- At similar intensities, increases in estradiol are greater
during the luteal phase when compared to follicular
phase (Consitt et al, 2002). - When comparing three varying intensities: light (20
min at 30–45%), heavy (20 min at 60–66%), and
exhaustive (20 min at 85–95%) exercise.
- The luteal phase showed a significant increase in
estradiol with heavy and exhaustive exercise. - The follicular phase showed a significant increase
with exhaustive exercise (Consitt et al, 2002).
•A significant decrease in metabolic clearance rate of
estradiol decreased after a short bout (10 min) of exer-
cise (Keizer et al, 70).
•Following 2 h of exercise, an increase in metabolic
clearance rate resulted in decreased estradiol levels.
- Resistance exercise: Untrained women had increased
estradiol levels with three sets of four exercises at
10 RM,in both luteal and follicular phase; increased
levels were similar to those found with endurance
exercise (Consitt et al, 2002). - Chronic exercise: Several studies report decreased
levels of estradiol following only 8 weeks of intense
endurance training (Consitt et al, 2002).
A. Testosterone- Endurance exercise:Various studies have shown a
short-term increase (returning to resting values within
hours of recovery) in testosterone after short bouts of
endurance exercise in women (Consitt et al, 2002).
TABLE 32-7 Parathyroid Hormone
GLAND HORMONE CONTROL ACTION ENDURANCE RESISTANCE CHRONIC
Parathyroid Parathormone Plasma Ca2+ Calcium homeostasis; Increased; compensate Increased Increased over time
stimulates bone growth; for decrease
increase plasma Ca2+; in plasma Ca2+
Phosphate regulation;lowers
Phosphate levels; bone
resorption by stimulating
osteoclasts and inhibiting
osteoblasts; activation of Vit-DTABLE 32-8 Ovarian Hormones
GLAND HORMONE CONTROL ACTION ENDURANCE RESISTANCE CHRONIC
Ovary Estradiol/Pro- FSH, LH Menstrual cycle; female sex Increase/decrease with acute Understudied Decreased;
gesterone characteristics; inhibition exercise; may be influenced intensity and
of glucose uptake; fat by menstrual phase and training volume
deposition, maintain bone intensity; metabolic dependent
density clearance rate may
influence change