Dianne

[Guest guest]

This is all greek to me but may help on your walking.

http://www.am-coll-nutr.org/jacn/vol_20/no_5/toc.htm

Effects of Dietary Fat and Endurance Exercise on Plasma Cortisol,

Prostaglandin E2, Interferon-gamma and Lipid Peroxides in Runners

Jaya T. Venkatraman, PhD, CNS, FACN, Xiaohong Feng, MS, and

Pendergast, EdD

Department of Physical Therapy, Exercise and Nutrition Sciences (J.T.V.,

X.F.), Department of Physiology (D.P.), State University of New York at

Buffalo, Buffalo, New York [jtv@...]

Objective: Exercise and the neuroendocrine and oxidative stress it

elicits on immune function is modulated by dietary fat intake. The

effects of increasing dietary fat on endurance exercise-induced

alterations (80% of VO2max for 2 hours) in the plasma levels of cortisol

and prostaglandin E2 (PGE2), interferon-gamma (IFN-gamma) and lipid

peroxides were investigated. As higher levels of cortisol, PGE2 and

lipid peroxides could be immunosuppressive, the effects of different

levels of dietary fat on these measures in runners were determined.

Methods: Healthy trained runners (males and females) consumed serially

15% fat diet (of daily energy), 30% fat diet and 40% fat diets for four

weeks each. In the last week of each diet period the subjects ran to

exhaustion at 80% of their VO2max and blood was drawn pre- and post-run.

Cortisol, IFN-gamma, PGE2 and lipid peroxides were determined using

standard techniques.

Results: Pre-exercise levels of plasma cortisol were elevated, IFN- was

unchanged and PGE2 and lipid peroxides decreased on the 40%F diet

compared to 30%F and 15%F. Post-exercise levels of plasma cortisol

(p<0.004), PGE2 (p=0.0057) and lipid peroxide levels increased

(p<0.0001) after endurance exercise on all diets. The rates of increase

of plasma cortisol levels during exercise were similar on all three

diets. Although absolute cortisol levels were higher in the high fat

group, the rate of increase of plasma cortisol level during exercise was

similar on each diet. The dietary fat levels did not affect IFN-gamma,

however, PGE2 and lipid peroxides decreased with increasing fat at

baseline at 40%F level (p< 0.01; 30%F vs. 40%F: p< 0.002; 15%F vs. 40%F:

p< 0.007).

Conclusions: Data from the present study suggest that higher levels of

fat in the diet, up to 40%, increase endurance running time without

adverse effects on plasma cortisol, IFN-gamma, and lipid peroxide

levels.