American Journal of Clinical Nutrition, Vol 23, 905-912, Copyright © 1970 by The American Society for Clinical Nutrition, Inc.

Vitamin C Supplementation Related to Physiological Response to Exercise in Smoking and Nonsmoking Subjects

¹ Associate Professor, School of Physical Education, University of Saskatchewan, Saskatoon, Saskatchewan
² Assistant Professor, School of Physical Education, University of Saskatchewan
³ Research Assistant, School of Physical Education, University of Saskatchewan
⁴ Director of Medical Services, Hoffmann-La Roche Ltd., Montreal, Quebec

Twenty smoking and twenty nonsmoking males (mean age, 24.5 years; standard deviation, 3.5) were required to run continuously on a level-grade, motor-driven treadmill for 3 min at 3 miles/hr, 3 min at 6 miles/hr, and 3 min at 9 miles/hr, before and after a 5-day, 2 g/day, vitamin C or placebo exposure. Following the standard double-blind protocol, 10 smoking and 10 nonsmoking subjects were given vitamin C daily while the remainder received the placebo. Plasma vitamin C levels were measured before and immediately following the 5-day treatment period and were found to fall within normal limits. Further, the vitamin C concentration of subjects on vitamin supplementation rose to saturation levels. The purpose of the study was to determine the effect of vitamin C saturation on respiratory adjustment and oxygen utilization before, during, and after exercise in smokers and nonsmokers. Measurements were made of minute ventilation (Vi), the ratio of tidal volume to vital capacity (Vt-Vc), oxygen uptake (Vo₂), and oxygen pulse (Vo₂/HR) at the various work levels as well as during preexercise and recovery. By employing a 2 x 2 x 2 factorial analysis of variance design, calculations were made of the differences in the before and after response of placebo versus vitamin C-saturated subjects in smokers and nonsmokers. The results of the various analyses performed on all parameters in all levels revealed no significant differences between the mean response of subjects given vitamin C and those given the placebo, whether they were smokers or nonsmokers. This was interpreted as providing evidence that daily supplementation of 2 g vitamin C had no effect on respiratory adjustment and oxygen utilization before, during, and after exercise in smoking and nonsmoking subjects.