Carbohydrate and Glutamine Supplementation Attenuates the Increase in Rating of Perceived Exertion during Intense Exercise in Hypoxia Similar to 4200 m

Abstract

The rating of perceived exertion (RPE) indicates the feeling of fatigue. However, hypoxia worsens the condition and can worsen RPE. We evaluated whether carbohydrate and glutamine supplementation alters RPE and physiological markers in running at 70% peak oxygen uptake until exhaustion in a simulated altitude of 4500 m. Nine volunteers underwent three running tests at 70% peak oxygen uptake until exhaustion: (1) hypoxia and placebo, (2) hypoxia and 8% maltodextrin, and (3) hypoxia after six days of glutamine supplementation (20 g/day) and 8% maltodextrin. The exercise and supplementation were randomized and double-blinded. Lactate, heart rate, haemoglobin O2 saturation (SpO2%), and RPE (6–20 scale) were analyzed at the 15th and 30th min. The level of significance was set at p ≤ 0.05. SpO2% decreased at the 15th and 30th minutes compared to resting in placebo, carbohydrate, and glutamine supplementation. RPE increased at the 30th minute compared to the 15th minute in placebo and carbohydrate supplementation; however, there was no difference in the glutamine supplementation condition. Heart rate and lactate increased after the 15th and 30th minutes compared to resting, similar to the three conditions studied. We conclude that previous supplementation with glutamine and carbohydrate during intense exercise in hypoxia similar to 4500 m can attenuate the increase in RPE by the increase in glycemia and can be a useful strategy for people who exercise in these conditions.

Effects of the Timing of Carbohydrate Intake on Metabolism and Performance in Soccer Players

“…HR in all experimental tests increased linearly over the course of exercise. This replicates findings from our previous study [ 42 ] and from related adult work [ 43 , 44 ]. Although there were no significant differences, the pre-exercise and mixed tests had 5 bpm less HR means ± SD of cycles one to five than the placebo test.…”

The Combined Effect of Glutamine and Creatine Supplementation on Body Hydration Level and Some Performance Parameters in Football Players

“…Furthermore, the reduction in symptoms of muscle damage due to glutamine supplementation may be attributed to various factors including increased availability of amino acids, additional energy intake from supplementation, and elevated protein synthesis. Moreover, Caris and Thomatieli-Santos (2020) suggested that glutamine intake (20 g/d for six days) prior to intense exercise may reduce the increase in RPE and could be a beneficial strategy for those engaged in exercise. Similarly, in a study assessing resistance-trained male athletes, Paiva et al (2020) administered creatine supplementation (20 g/d) for seven days.…”

Cystine/Glutamine Mixture Supplementation Attenuated Fatigue during Endurance Exercise in Healthy Young Men by Enhancing Fatty Acid Utilization

“…Acute or chronic glutamine supplementations have been widely applied to take advantage of its antioxidant, anti-inflammatory, and immuno-regulating capacity. Recently, Caris and colleagues reported that 6-day glutamine (20 g/day) supplementation enhances in-trial glycemia and attenuates the increase in RPE ( n = 9, treadmill exercise to exhaustion, 70% VO 2max ) [ 34 ]. Cystine is an oxidized form of cysteine.…”