NMN Combined with Exercise May Boost Aerobic Capacity
Reviewed and Updated By: Emily Parsell, RDN
It’s well-known that aerobic exercise supports cardiovascular, metabolic, and lung health. The term aerobic means “with oxygen,” so this type of exercise facilitates the movement of oxygen and nutrients to the muscles via blood for fuel. We also know that sedentary older adults tend to have diminished aerobic capacity — a measure of how well the cardiovascular system can deliver oxygen to muscles — with estimates of a 15% reduction per decade once we reach our 50s. This decline may be due to several reasons, including altered blood flow from arteries stiffening, skeletal muscle function dwindling, or the accumulation of inflammatory compounds causing the quality of our endothelium — the single layer of cells lining the inside of our blood vessels —to deteriorate.
But, is there anything older adults can do to slow down this decline? Research published in the Journal of the International Society of Sports Nutrition suggests that NMN, or nicotinamide mononucleotide, may be one such compound to support aerobic capacity with age. This research team, based out of Guangzhou Sport University in China, finds that combining NMN with exercise increases several markers of aerobic function in healthy adults, setting the stage for using this compound to support physical performance at any age.
Why Our Bodies Need NAD+
With age, NAD+ levels progressively decline, leading many researchers to target low NAD+ as a leading cause of age-related physical and cardiovascular dysfunction. NMN is thought to support physical and aerobic function due to its nature as a precursor to NAD+ (nicotinamide adenine dinucleotide). This vital and bioenergetic coenzyme is needed to facilitate just about every cellular process in the body.
Previous research has found that supplementing mice with another NAD+ precursor, nicotinamide riboside (NR), boosted NAD+ levels in their skeletal muscle and improved markers of aerobic capacity when combined with exercise. However, despite a growing number of animal studies showing that NAD+ precursors support physical activity, aerobic capacity, or endurance, research in humans has been limited — until now, with this study authored by Liao and colleagues.
Researchers Randomize Runners to Take NMN
The Guangzhou-based research team randomly split 48 healthy amateur runners (aged 27 to 50) into four groups. Each had ten males and two females and received one of the following interventions: low-dose NMN (300 mg of NMN powder per day), medium-dose NMN (600 mg per day), high-dose NMN (1200 mg per day), or a control group receiving a placebo powder.
In addition to taking the daily NMN (split up into two doses per day), all four groups also performed five to six sessions of running or cycling per week. Additionally, the research team measured several aerobic and physical function markers at the start of the study and after six weeks.
Supplemental NMN Supports Strong Aerobic Function
After the study’s completion, Liao and colleagues found that supplemental NMN boosted aerobic capacity more than the exercise-only group in a dose-dependent manner — meaning, the higher doses of NMN produced a more significant effect.
All three NMN groups exhibited increases in their first ventilatory thresholds (VT1) — the point at which breathing increases faster than the maximum oxygen consumption rate (VO₂max). Essentially, VT1 measures the intensity of activity at which your breathing becomes so labored that you can’t inhale as much air as you feel your body needs, leading to an inability to speak comfortably.
The NMN groups also had significant increases in VT2 — a more intense version of VT1, where breathing becomes so labored that someone would be unable to speak at all during exercise. A sedentary person will reach their ventilatory thresholds at much lower exercise intensities than a more physically active person, and increasing the thresholds would enable someone to continue with physical activity for a more extended period. Supplemental NMN also boosted measurements of aerobic power at VT1 and VT2, which is the muscles’ ability to utilize oxygen received from the heart and lungs to produce energy.
These results were all dose-dependent, with the high-dose NMN groups experiencing approximately doubled the benefits than the low-dose group. The only test that did not follow the dose-dependent manner was the single-leg stance test — measuring balance abilities — which only significantly improved in the medium-dose (600 mg/day) group. However, not all measured biomarkers were improved by NMN, including VO₂max, maximum heart rate, peak aerobic power, body composition, grip strength or push-up abilities.
Future Directions for NMN and Physical Function
This study provided the first-of-its-kind evidence that supplemental NMN increases aerobic capacity in humans, which may translate to supporting older adults with diminished physical function. And, although the lower dose of NMN (300 mg/day) still did exhibit the same benefits, they were about half that of the highest dose group (1200 mg/day).
The researchers speculate that these physical improvements are due to an increased ability of skeletal muscles to utilize oxygen when exposed to NMN. This type of muscle — the kind that enables us to move our bodies, no matter how minor — is sensitive to NAD+ and has been shown to benefit from NAD+ boosters in other studies.
However, more research is still needed, as this study was relatively small and not entirely diverse. There were only eight females, and all of the participants were younger or middle-aged Chinese adults. As Liao and colleagues remark, “Additional studies are needed to determine if there exist gender differences and improvement in vascular endothelium function, and whether the combination of NMN supplementation and exercise leads to increases in capillary density, blood flow and mitochondrial function.”
The authors conclude, “The results of this study reveal that exercise training combining with the supplementation of NMN further lift ventilatory threshold in amateur runners; the benefit is dose-dependent and muscle-related.”
Crisol BM, Veiga CB, Braga RR, et al. NAD+ precursor increases aerobic performance in mice. Eur J Nutr. 2020;59(6):2427-2437. doi:10.1007/s00394-019-02089-z
Liao B, Zhao Y, Wang D, Zhang X, Hao X, Hu M. Nicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners: a randomized, double-blind study. J Int Soc Sports Nutr. 2021;18(1):54. Published 2021 Jul 8. doi:10.1186/s12970-021-00442-4