PHYSIOLOGICAL-EFFECTS OF DOWNHILL SKIING AT MODERATE ALTITUDE IN UNTRAINED MIDDLE-AGED MEN

To evaluate whether occasional strong physical activity at moderate al titude for several consecutive days is acceptable in untrained middle- aged people, 10 men (age range, 46-59 years) underwent physical examin ations before (control day, D-0), during (D-1-D-8), and after 1 wk of leisure alpine skiing. With respect to D-0, the resting concentration of plasma noradrenaline (NOR) increased transiently (p < 0.01) on D-2 and then increased to a maximal value from D-6-D-8 (p < 0.01). There w as no significant change in the concentration of adrenaline. Although maximal voluntary contraction of knee extensors diminished on D-3 (P < 0.05), that of the digit flexors did not change. Heart rate (HR) and blood pressure at rest in the evening were always higher than control values except on D-4 (forced rest). After the stay, there was a reduct ion in sympathetic activity. This was reflected by a return of NOR to its control value, a decrease in resting HR (64.2 [11.4] beats per min ute [bpm]; control: 71.1 [10.1] bpm, P < 0.02), a tendency for triglyc eride and insulin resistance to decrease, and a significant increase i n alipoprotein A(1)/alipoprotein A(2) (P < 0.01). Our results show tha t despite signs of fatigue on D-3, the effects of physical activity th at is relatively intense (HR > 70% maximal HR) together with mild hypo xia are well tolerated by untrained middle-aged men and that the contr olled practice of downhill skiing may be accepted into a program to lo wer cardiovascular risk factors.