Low doses of D-ribose raise the level of fitness and lower the perception of fatigue in baby boomers aged 45-65 who perceive themselves as fatigued. The doses range from 0.100 grams to 3.0 grams, bid, for a total of 0.200 to 6.0 grams daily. Objective measures of cardiopulmonary parameters confirm the improvement of fitness and questionnaires confirm that quality of life and mental states are improved with D-ribose administration.