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.

Introduction: Bicarbonate enhances muscle performance during strenuous exercise, but its effect on performance during normal activity in older subjects is unknown.

Methods: 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.

Results: 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.

Conclusions: 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.

Conflict of interest statement

Conflicts of interest None.

Figures

Fig. 1

Mean 3-month change in NAE by treatment group in the men and the women. Within sex, bars labeled a differ significantly from bars labeled b, P<0.001

Fig. 2

Effect of treatment with bicarbonate versus no bicarbonate on mean change in peak double leg press power output (adjusted for baseline value, tester concordance, and changes in urinary sodium/Cr and potassium/Cr). Open bars represent no bicarbonate and filled bars represent bicarbonate. a In peak double leg press power at both 40% and 70% of 1-RM, the treatment groups differed significantly in the women (P=0.006 and P=0.003, respectively) but not in the men

Fig. 3

Mean double leg press power output at 40% and 70% 1-RM by NAE/Cr tertile at the end of the study, adjusted for baseline value, and for sodium/Cr and potassium/Cr. a, b Like symbols indicate significant differences between tertiles at P<0.05

Fig. 4

Effect of treatment with bicarbonate versus no bicarbonate on mean change in urinary nitrogen/Cr and NAE/Cr (adjusted for baseline value and changes in urinary sodium/Cr and potassium/Cr). Open bars represent no bicarbonate and filled bars represent bicarbonate. a The treatment groups differ significantly in the women (P=0.004) but not the men