5-Hydroxymethylfurfural and α-ketoglutaric acid supplementation increases oxygen saturation during prolonged exercise in normobaric hypoxia
Abstract
Abstract. This double-blinded, randomized and placebo-controlled, crossover study investigated whether α-ketoglutaric-acid (α-KG) and 5-hydroxymethylfurfural (5-HMF) supplementation improves exercise performance in hypoxia and affects physiological responses during the exercise task. Eight moderately trained male participants (age: 25.3 ± 2.0 y, VO2max: 48.0 ± 8.3 ml/min/kg) performed an incremental exercise test to exhaustion in normoxia and two 2-hour cycle time trial (TT) tests in hypoxia (3,500 m) each separated by 1-week. Prior to the TT, participants supplemented with either α-KG and 5-HMF or placebo (random order). Supplementation did not improve TT performance at altitude and did not affect heart rate, effort perception and oxidative stress levels (p > 0.05). Oxygen saturation (SpO2) was enhanced during the α-KG and 5-HMF supplementation trial (79.5 ± 3.3 vs. 78.2 ± 3.7%, p = 0.026). Even though TT performance was unaffected, the enhanced SpO2 – possibly originated from changed O2-affinity – deserves further consideration as the exercise performance decline at altitude is strongly linked to the SpO2 decline. The inclusion of moderately fit participants, not specifically cycle trained, might have prevented any visible performance enhancement.
References
1 (2007) Effect of altitude on the heart and the lungs. Circulation. 116 (19): 2191–202.
2 (1998) Maximal and submaximal exercise performance at altitude. Aviat Space Environ Med. 69 (8): 793–801.
3 (2002) Work at high altitude and oxidative stress: antioxidant nutrients. Toxicology. 180 (2): 107–19.
4 (2006) Linear decrease in VO2max and performance with increasing altitude in endurance athletes. Eur J Appl Physiol. 96 (4): 404–12.
5 (1997) The decrease of maximal oxygen consumption during hypoxia in man: a mirror image of the oxygen equilibrium curve. J Physiol. 498 (Pt 1): 231–7.
6 (2006) Effects of short-term acclimatization to altitude (3200 m) on aerobic and anaerobic exercise performance. Int J Sports Med. 27 (8): 629–35.
7 (2007) Mitochondria, oxidative stress and cell death. Apoptosis. 12 (5): 913–22.
8 (2007) Vitamin E prevents hypobaric hypoxia-induced mitochondrial dysfunction in skeletal muscle. Clin Sci (Lond). 113 (12): 459–66.
9 (1988) Influence of vitamin E on physical performance. Int J Vitam Nutr Res. 58 (1): 49–54.
10 (2006) Changes in ventilatory threshold at high altitude: effect of antioxidants. Med Sci Sports Exerc. 38 (8): 1425–31.
11 (2014) Effects of antioxidant supplementation on exercise performance in acute normobaric hypoxia. Int J Sport Nutr Exerc Metab. 24 (2): 227–35.
12 (2013) Short-term supplementation with alpha-ketoglutaric acid and 5-hydroxymethylfurfural does not prevent the hypoxia induced decrease of exercise performance despite attenuation of oxidative stress. Int J Sports Med. 34 (1): 1–7.
13 (2000) Physiological models to understand exercise fatigue and the adaptations that predict or enhance athletic performance. Scand J Med Sci Sports. 10 (3): 123–45.
14 (2000) Limiting factors for maximum oxygen uptake and determinants of endurance performance. Med Sci Sports Exerc. 32 (1): 70–84.
15 (2002) Alpha-ketoglutarate-supplemented enteral nutrition: effects on postoperative nitrogen balance and muscle catabolism. Nutrition. 18 (9): 725–8.
16 (2007) The impact of preoperative micronutrient supplementation in lung surgery. A prospective randomized trial of oral supplementation of combined alpha-ketoglutaric acid and 5-hydroxymethylfurfural. Eur J Cardiothorac Surg. 32 (5): 776–82.
17 (2004) Enzymes of the L-arginine to nitric oxide pathway. J Nutr. 134, 2748–51.
18 (2018) Dietary nitrate and physical performance. Annu Rev Nutr. 38, 303–28.
19 (2012) Improved training tolerance by supplementation with α-Keto acids in untrained young adults: a randomized, double blind, placebo-controlled trial. J Int Soc Sports Nutr. 9 (1): 37.
20 (2012) Increased hemoglobin O2 affinity protects during acute hypoxia. Am J Physiol Heart Circ Physiol. 303 (3): H271–81.
21 (2011) The protective role of 5-HMF against hypoxic injury. Cell Stress Chaperones. 16 (3): 267–73.
22 (2019) Cardiovascular parameters in a swine model of normobaric hypoxia treated with 5-hydroxymethyl-2-furfural (5-HMF). Front Physiol. 10, 395.
23 (2015) Effects of short-term antioxidant supplementation on oxidative stress and exercise performance in the heat and the cold. Int J Physiol Pathophysiol Pharmacol. 7 (2): 98–104.
24 (1995) Criteria for maximal oxygen uptake: review and commentary. Med Sci Sports Exerc. 27 (9): 1292–301.
25 (2011) Reactive oxygen species: impact on skeletal muscle. Compr Physiol. 1 (2): 941–69.
26 (2015) Impact of oxidative stress on exercising skeletal muscle. Biomolecules. 5 (2): 356–77.