N.O. idea about Nitric Oxide?
Nitric oxide (NO) is a vasodilator AKA a chemical that enables your arteries to dilate, increasing in diameter to enable increased blood flow (fondly known as ‘THE PUMP’)1. Everyone appreciates a #vascular insta pic… but NO supplementation can enhance exercise and muscle function by increasing the efficiency of the muscle at a cellular level.
Muscle cells and mitochondria
Every muscle cell contains thousands of mitochondria. Mitochondria are the little power engines responsible for breaking down nutrients to provide energy (a process called cellular respiration). One common form of energy, aerobic respiration, requires oxygen (no wonder breathing rate increases, particularly in the rare occasion of HIIT or cardio). Those endurance athletes among us probably have larger amounts of mitochondria per muscle fibre. In fact, to meet the demands of aerobic exercise, one known metabolic adaption is to increase the production of mitochondria. So off you go to do a whole bunch of cardio… just kidding! Aerobic capacity can also be enhanced by increasing the efficiency of pre-existing mitochondria, and that is exactly what NO supplementation can do!
Increased aerobic capacity
Nitric oxide has the ability to improve the efficiency of muscle mitochondria. Although the exact mechanism is still under debate, it is widely accepted that NO supplementation can influence the production of important mitochondrial proteins (necessary “parts” for the engine to function). These changes result in a reduced oxygen requirement during physical exercise (basically you’re swapping a petrol guzzler for a fuel efficient Ford Fiesta)2. So, it is no wonder endurance athletes can be found chugging down beetroot juice (a naturally high dietary NO supplement).
Increased force production
Hopefully the lifters are still reading after the brief cardio discussion. Nitrate supplementation has also shown the ability to increase contractile force in fast twitch muscles: fibres with a high force capacity but fast fatigue3. Once again, this improvement is due to modifying muscles at a cellular level, this time to increase calcium handling. In muscle cells, calcium release is essential for initiating muscle contraction. Recent studies have shown that NO supplementation enables a greater force production with lower muscle stimulation. Essentially this could translate to lifting greater loads with a reduced effort #goals.
Supplement time…
NO supplements often contain either Citrulline and/or L-arginine. Both of these amino acids are precursors of NO; Citruiline is broken down to produce arginine, which subsequently promotes NO production4. However, current research suggests that Citruline is superior as it bypasses digestion and directly enters the bloodstream. Some of the desirable effects of natural L-citrulline (natural form produced by the body), can be enhanced via the synthetic addition of an energy boosting malic acid to form Citruline Malate (CM). CM is relatively new but studies show promising results5. Check out the L-arginine, Citrulline and CM containing supplements:
- Rule 1: R1 Train (L-arginine)
- Metabolic Nutrition: E.S.P Pre Workout, PSP Pre Workout (L-Citruline)
- Animal: Rage XL, Juiced Aminos (CM)
The benefits of NO supplementation are supported in the scientific literature. For more details, check out the studies that I have referred to:
- Stamler JS, Meissner G. Physiology of nitric oxide in skeletal muscle. Physiol Rev. 2009;81:209–37.
- Larsen FJ1, Schiffer TA, Borniquel S, Sahlin K, Ekblom B, Lundberg JO, Weitzberg E. Dietary inorganic nitrate improves mitochondrial efficiency in humans. Cell Metab.2011 Feb 2;13(2):149-59. doi: 10.1016/j.cmet.2011.01.004.
- Hernández A, Schiffer TA, Ivarsson N, et al. Dietary nitrate increases tetanic [Ca2+]i and contractile force in mouse fast-twitch muscle. The Journal of Physiology. 2012;590(Pt 15):3575-3583. doi:10.1113/jphysiol.2012.232777.
- Lundberg JO, Weitzberg E. NO-synthase independent NO generation in mammals. Biochem Biophys Res Commun. 2010;396:39–45.
- Glenn J.M, Gray M, Jensen A et.al Acute citrulline-malate supplementation improves maximal strength and anaerobic power in female, masters athletes tennis players. European Journal of Sport Science. 2016, 1-9.
For explanation of calcium and muscle contraction visit: