Deep Dive: Will nitrates improve your training performance? It depends!

Both athletes and recreationally active people commonly use dietary supplements in an attempt to improve their physical performance. One such supplement is nitrate (NO₃⁻), a molecule which is produced in the body in small amounts, and which is obtainable through the diet mainly through the consumption of some vegetables^[1] (e.g., lettuce, beetroot, and spinach).

In the body, dietary nitrate is reduced to nitrite, and then to nitric oxide (NO) through what is called the nitrate-nitrite-nitric oxide pathway^[2], shown in Figure 1. NO, through its effects on vasodilation^[3], mitochondrial respiration^[4], calcium handling^[5], and glucose uptake^[6], may improve muscle function and reduce fatigue, thereby enhancing physical performance.

Figure 1: How dietary nitrate may ultimately boost performance

Reference: Jones. Sports Med. 2014 May.^[7]

While NO₃⁻ supplementation should, theoretically, improve training performance, there is substantial variability in its ergogenic effects within and between trials. This variability could be due to several factors, including biological sex, aerobic fitness level, environmental oxygen concentrations, exercise parameters, and the dosage and timing of NO₃⁻ supplementation. The meta-analysis under review pooled the available trials together to examine the overall impact of nitrate supplementation on training performance, and is the first meta-analysis to have examined the potential influence of the aforementioned factors on NO₃⁻ ergogenicity.

Although nitrate supplementation is common in athletes and recreationally active people looking to improve their physical performance, there is substantial variability in the ergogenic effects of nitrate within and between trials. This variability could be due to several individual, environmental, exercise, and supplementation-related factors. The meta-analysis under review aimed to examine the potential influence of these factors.