Impact of supplementation with bicarbonate on lower-extremity muscle performance in older men and women

Abstract

This study describes the impact of bicarbonate treatment for 3 months on net acid excretion (NAE), nitrogen excretion, and muscle performance in older men and women. Bicarbonate reduced NAE, and the decrement was associated with a decrease in nitrogen excretion. Treatment also improved muscle power and endurance in the women. Bicarbonate enhances muscle performance during strenuous exercise, but its effect on performance during normal activity in older subjects is unknown. In this trial, healthy subjects age 50 and older were randomized to 67.5 mmol of bicarbonate or to no bicarbonate daily for 3 months. Changes in lower-extremity muscle power, endurance, urinary nitrogen, and NAE were compared across treatment groups in the 162 participants included in the analyses. In the men and the women, bicarbonate was well tolerated, and as expected, it significantly decreased NAE. The change in NAE correlated with change in nitrogen excretion in women (r = 0.32, P = 0.002) with a similar trend in men (r = 0.23, P = 0.052). In the women, bicarbonate increased double leg press power at 70% one repetition maximum by 13% (P = 0.003) compared with no bicarbonate and improved other performance measures. Treatment with bicarbonate had no significant effect on muscle performance in the men. Ingestion of bicarbonate decreased nitrogen excretion and improved muscle performance in healthy postmenopausal women. The bicarbonate-induced decline in NAE was associated with reduced nitrogen excretion in both men and women. These findings suggest that bicarbonate merits further evaluation as a safe, low-cost intervention that may attenuate age-related loss of muscle performance and mass in the elderly.