Written by: Katie Kuhlmann MS – Dietetic Intern, University of Houston
Edited by: Brett Singer MS,RD,CSSD,LD – Sports Dietitian, Memorial Hermann IRONMAN Sports Medicine Institute
- If you're working out or training outdoors during the summer months, other cold water therapy, what other cooling methods can be used?
- The need for cooling an athlete during exercise
- Menthol is used as an ergogenic aid to improve athletic performance
What is Menthol?
This minty flavor chemical compound is found in certain plants and is extracted as an essential oil. It can be found naturally in sources such as peppermint. Menthol is used in several products and foods like beverages, certain candy such as mints, and gum. These products all elicit a cooling sensation in the mouth when eaten due the menthol compound.
While we often think of it as a flavor within food, menthol has also become popular amongst athletes as a potential ergogenic aid. As already mentioned, it can be used in foods to give it a minty, cooling flavor that can be taken orally. Menthol can also be used as a topical cream or gel to provide analgesic sensations, anti-inflammatory effects, and a cooling sensation to painful areas on the body (Kamatou et al., 2013).
Importance of cooling an athlete during exercise.
When an athlete is training or practicing outdoors in a hot environment, core temperature will rise placing physiological strain on their body. In addition to staying well hydrated, athletes can utilize cooling tactics to help regulate their core temperature and improve performance.
Current cooling strategies include cold water immersion, drinking ice slushies or cold fluids, or cold towels/garments.
If the skin is cooled down, core temperature cools down, blood can be redirected back to the core to lower strain, and the athlete’s perceived exertion is reduced. In turn, the athlete can continue to participate in exercise for a longer period with better performance.
Recently, menthol has been used as newer cooling aid for athletes and has been shown to provide positive effects on performance as an ergogenic aid.
How does menthol cool an athlete?
There are two ways menthol has been used for cooling: external application of gels or creams or internally by mouth rinsing/ingestion.
When menthol is either ingested or rinsed in the mouth, it interacts with the sensory nerves in the oral cavity. This activates the sensory pathway causing a perceived feeling of cooling.
External application of menthol on a targeted body area allows the feeling of a cool sensation to occur that has been shown to increase an athletes’ performance. It gives the athlete a cooling sensation without cooling their body temperature. Menthol sprays, creams, gels, and tapes provide cooling effects to help an athlete reduce their inflammation for their sport or exercise.
When an athlete perceives that they “feel” cooler, their discomfort associated with heat is reduced. When this happens, the athlete’s perceived exertion is reduced, and their performance outcomes have been shown to be improved.
Recent research has shown that mouth rinsing or ingesting menthol has improved time rials, time to exhaustion, and rate of perceived exertion all by an average of ~6% (Jeffries et al., 2019, Mundel et al. 2010). However, a mouth rinse alone has been shown to provide positive effects without ingestion since the sensory receptors are located in the oral cavity. A mouth rinse and an ingestion provide the same effects, but a mouth rinse alone may be a simpler method to provide the same benefits.
Some research provides evidence that applying menthol topically to a single targeted area such as the face had greater benefit than applying a topical on the whole body, which showed negative outcomes. The face has greater sensitivity to cold, and by applying the topical to the face alone exercise duration was improved among cyclists who completed trials at constant rating of perceived exertion while under heat stress (Schlader et al., 2011).
Much of the current evidence provided has been analyzed with endurance-related sports. There is limited evidence that supports strength athletes, and therefore must be kept in mind when administering menthol as a cooling aid.
Current recommendation of menthol use for athletes:
The use of menthol has shown to be most beneficial when administered orally. Current mouth-rinse solutions included 0.01% menthol concentration in beverages or ice slushies.
Menthol mouth-rinsing is recommended for athletes who participate in moderate endurance events lasting between 15 – 60 minutes in duration while in the heat (Best, 2021).
Topical application has shown to be beneficial for target regions of the body. Typical range used in research was 4-9% menthol in topical solutions. Some over-the-counter topicals that can be purchased range from 4-16% menthol concentration depending on strength of topical.
It is important to understand these concentrations because a concentration of <2% gives a cooling sensation, 2-5% provides local analgesic properties or possibly irritation (Cliff et al., 1994, Eccles, 1994). Any topical solution >10% may cause burning sensations (Yosipovitch et al., 1996).
With all this to say, current research is limited for the use of food sources such as minty candy, gum, lozenges, etc., and their effects on athletic performance. Most mouth rinsing solutions used contained the chemical L-menthol dissolved in water within a laboratory setting for research purposes. One study created a menthol energy gel that has positive effects on performance at a 0.1% solution, but the energy gel used is currently not available for public (Stevens et al., 2020). Athletes may not have access to the chemical L-menthol, and therefore should seek more applicable and safer ways to add it to their routine.
If an athlete would like to use menthol as an ergogenic aid, they may try food sources that contain menthol. These sources include menthol lozenges, gum, or sports gels/powders that contains menthol.
Menthol Use Summary
Athlete safety is ultimately the goal when using supplements for performance and should be cautioned if menthol is pursued for its ergogenic benefits in the heat during endurance exercise or other sports. Below are several considerations an athlete should have in mind:
- An athlete can work with a sports dietitian to determine if and when menthol may be a useful tool for them to use during exercise.
- Practice with different dosage (concentrations) and frequency needed during training to develop preferences. One study showed that administering menthol near exhaustion (~85% of time to exhaustion) has shown positive effects for extending exercise time during cycling (Jeffries et al., 2018). Additionally, another study analyzing cyclists provided evidence for a 10-second mouth rinse frequency at every 10 minutes during exercise also extended exercise time (Mundel et al., 2010)
- There are various food sources and an emerging line of sports nutrition products which contain menthol. Practice using various sources to determine which is best suited for the individual athlete
Have questions or want to set up a consultation? Please contact Memorial Hermann IRONMAN Sports Medicine Institute Sports Dietitian Brett Singer at email@example.com. or by phone at (713) 526-6143.
You can also follow him on twitter @bsinger10 or on Instagram @bsinger_sportsrd.
Visit our website to learn more about the athletic performance solutions we provide at Athlete Training and Health.
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