Per endurance athletes, extreme temperatures and altitude can affect normal physiological responses to exercise and, in some cases, sports performance is adversely affected. Although the scientific evidence is not complete on this front, the use of altitude training remains a widespread practice in many sports. The purpose of this article is to understand its physiology and any nutritional adjustments that can be put in place to best guarantee athletic performance .

The detrimental effects of altitude and heat on sports performance have been the subject of many comprehensive scientific review articles (Saunders et al. 2009; Nybo et al. 2014).

Altitude is associated in particular with a decrease in barometric pressure and a corresponding reduction in oxygen availability . The extent of altitude can be classified as low (1000-2000m), moderate (2000-3000m), high (3000-5000m) or extreme (> 5000m) (Levine & Stray-Gundersen 2002).

In detail, even hypoxia (i.e. the condition of oxygen deficiency in the body's tissues) causes ventilation, heart rate and the perception of effort to be high compared to the values ​​that would occur with a similar workout. but carried out at sea level. Furthermore, the normal endocrine response (e.g. the release of adrenaline, noradrenaline and cortisol) to exercise is typically amplified at altitude. This promotes a greater use of carbohydrates as fuel than when training is done at sea level (Berglund 1992).

Altitude also increases oxidative stress , which is independent of exercise (Heinicke et al. 2009). Already after a few days in altitude there is a loss of plasma volume due to the increase in blood pressure and diuresis. In fact, hypoxia stimulates the production of the glycoprotein erythropoietin (EPO) by the kidneys, promoting many adaptations and benefits for athletes, particularly for those of endurance. (Gore et al. 2013).

If athletes continue to train at a moderate altitude for 2-3 weeks and are exposed to an ideal diet and training program, numerous physiological adaptations can occur that facilitate tissue oxygenation. The most widely documented and discussed adaptation to moderate altitude training is an increase in red blood cell mass, which can increase by approximately 1% for every 100 hours of exposure (Gore et al. 2013).

From a nutritional standpoint, understanding the unique stresses and adaptations associated with altitude exposure provides rationale for modifications and strategies aimed at developing a specific diet.

Per example, low iron levels before and during altitude training can compromise the adaptive effects of high altitude training. Athletes with low iron reserves (i.e. ferritin values ​​<30 ng / mL) may not respond to adaptations due to altitude training, because many are closely related to this parameter. The general recommendation for athletes with low iron status is to increase iron intake and endogenous iron stores through an iron-rich diet and, if necessary, use oral iron supplementation for 1-2 months prior to altitude exposure (Friedmann et al. 1999).

Athletes who pursue weight loss and who undergo prolonged low-energy diets are at risk of further losing weight at altitude; this can compromise the adaptive responses of the organism, in particular the mechanism of erythropoiesis. In fact, the energy requirement is higher when you are at altitude. In a clinical setting, the efficacy of EPO was improved when patients on long-term hemodialysis were given energy supplements equivalent to 475 kcal (2000 kJ) per day (Hung et al. 2005). Hence, for these patients, the increased energy intake acted as a stimulus for EPO activity.

Now let's see in detail how to behave at altitude for the management of macronutrients , hydration and what are the recommended supplements for those who carry out intense activities at high altitude.


The need for fluids increases when you train in a hypoxic environment (i.e. with a lack of oxygen, such as at high altitudes), due to dry air and therefore low humidity, increased water lost through sweat or lungs , a higher respiratory rate, associated with both life and exercise in hypoxia, and an increase in basal metabolic rate (BMR).

Per an athlete undertaking high intensity training at altitude, sports drinks can be extremely helpful . The hydration status of male skiers was monitored during a training period at 1800 meters and the results indicated that sports drinks were more effective than water in preventing plasma volume loss and maintaining fluid balance (Yanagisawa et al . 2012).

During periods of high altitude training, a decrease in voluntary food intake may also occur due to hypoxia-related appetite suppression. This, combined with a corresponding increase in basal metabolic rate, will certainly result in an undesirable energy deficit, which can impair performance and lead to weight loss. A useful tip may be to drink continuously (every 10-20 minutes) sips of water (and possibly drinks with electrolytes), despite the fact that the thirst is not felt: this can help prevent dehydration at high altitudes, especially in case of of endurance sports.


Since, as explained above, during the initial phase of adaptation to the height, a reduction in appetite by athletes could intervene, it would be prudent, at least for the acclimatization period, to ingest foods rich in CHO (carbohydrates) at each meal. and for snacks consumed between meals and during training. It has also been shown that diets high in CHO can also improve physical and mental intolerance to hypoxia (Consolazio et al. 1969). The intake of carbohydrates, especially slow-release carbohydrates, is essential before, during and after activity, because they improve performance, ensure the restoration of muscle glycogen stores and counteract fatigue. A good amount, for activities such as mountaineering, could be 60-75g of CHO / hour of activity.


As seen from initial animal studies, hypoxia impairs muscle protein synthesis regardless of maintaining energy balance (Brugarolas et al. 2004). Prolonged non-optimal energy and protein intake accompanied by weight loss therefore promotes a decrease in lean mass.

At sea level, 20-25 grams of high-quality protein consumed after exercise is sufficient to maximize protein synthesis (Witard et al. 2014). Athletes who develop negative energy balance at altitude will require slightly higher protein intakes than those normally recommended for athletes engaging in heavy training at sea level. Branched-chain amino acids, and in particular leucine(found naturally in foods rich in high quality Protein), are useful for the regulation of postprandial muscle protein synthesis (Koopman et al. 2006). As is known, a correct intake of amino acids is essential to counteract muscle catabolism, to perform a "plastic" function of muscle building and for energy support (creatine, for example, is an important source of reserve energy, which the body uses when ATP production is still too low).


The relatively high percentage of energy from dietary fat appears to be well tolerated at high altitudes. In a study of soldiers living and exercising at 3800 meters, 324 g / g of dietary fat, which contributed 47% of the total energy of the diet, was not associated with any gastrointestinal problems or with the development of ailments such as constipation or diarrhea (Rai et al. 1975). Mountaineers are often addicted to high-fat foods (e.g. chocolate, nuts, or dried fruit in general) due to their high energy density, palatability and convenience in transportation. High fat intake may also be of benefit to those elite athletes who train for certain periods at altitude and who find it difficult to maintain weight and eat a higher volume of food to meet their higher energy needs. This is because lipids are the most densely caloric macronutrient (in fact, 1 g of fat corresponds to an energy intake of 9 kcal).


Various plant extracts and supplements of natural origin can support sports performance, especially during endurance activities or carried out at high altitudes. In fact, although the supplementary accuracy useful to support endurance sports is known, the positive effect of some supplements and plant extracts on high altitude training is much less known .

At high altitudes, high physical effort and various adaptations are required of our body, which include thermoregulation , heartbeat , respiration and production of red blood cells . Underestimating nutrition and the intake of micronutrients is a subjective danger: that is, attributable only to our choices. So how can we support our diet?

Here too, although there are not many studies yet, we would like to name 3 substances in particular for their beneficial effects:

  • Tyrosine. It is the starting amino acid for the synthesis of important neurotransmitters, such as dopamine, adrenaline and noradrenaline. These substances are very important for the adaptation process to intense psycho-physical stress and for this reason they are ascribed to this substance adaptogenic properties. It is usually used by athletes as a supplement to improve performance, and is particularly effective in case of fatigue. Furthermore, it has been shown that during exposure to cold, an increase in sympathetic nerve activity stimulates vasoconstriction (VC) of the cutaneous vessels to minimize heat loss: L-tyrosine (substrate for the production of catecholamines) is being able to increase the CV,
  • Rhodes . The extract of the Rhodiola crenulata plant has been seen to have positive effects on high altitude training. In several studies focusing on hypoxia, levels of EPO, contained in red blood cells and hemoglobin, an improvement of these parameters was associated when the athlete supplemented his diet with the intake of rodiola. In particular, this plant, already known in traditional Asian and European folk medicine, is associated with anti-stress functions, reducing the appearance of fatigue, improving performance and preventing the common "altitude sickness".
  • Cordyceps . Similarly to Rhodiola, the extract of the Cordyceps sinensis plant has been associated with stimulation of vasodilation, the possibility of stimulating the release of Nitric Oxide and increasing the efficiency of oxygen use by the tissues. These effects, given by its supplementation, have the potential to improve the performance of endurance sports at high altitude.


Both at a professional and amateur level, there is emerging scientific evidence that indicates how high-altitude training can translate into "advantage" when you return to training in normal conditions. To maximize this advantage, nutrition and supplementation are fundamental, making the correct changes in order to better support the physiological changes that occur in the body. The purpose of the article is for information only, and any person who decides to undertake a specific nutritional program must necessarily contact their doctor (or a figure authorized by current law as a dietician or nutrition biologist) for specific information for their situation .



Saunders PU, Pyne DB, Gore CJ. Endurance training at altitude. High Alt Med Biol 2009;10:135–48.

Nybo L. Exercise and heat stress: cerebral challenges and consequences. Prog Brain Res 2007;162:29–43.

Levine BD, Stray-Gundersen J. Dose-response of altitude training: how much altitude is enough? Adv Exp Med Biol 2006;588:233–47.

Berglund B. High-altitude training. Aspects of haematological adaptation. Sports Med 1992;14:289–303.

Heinicke I, Boehler A, Rechsteiner T, et al. Moderate altitude but not additional endurance training increases markers of oxidative stress in exhaled breath condensate. Eur J Appl Physiol 2009;106:599–604.

Gore CJ. The challenge of assessing athlete performance after altitude training. J Appl Physiol 2014;116:593–4.

Friedmann B, Jost J, Rating T, et al. Effects of iron supplementation on total body hemoglobin during endurance training at moderate altitude. Int J Sports Med 1999;20:78–85.

Hung SC, Tung TY, Yang CS, Tarng DC. High-calorie supplementation increases serum leptin levels and improves response to rHuEPO in long-term hemodialysis patients. Am J Kidney Dis 2005;45:1073–83.

Yanagisawa K, Ito O, Nagai S, Onishi S. Electrolyte-carbohydrate beverage prevents water loss in the early stage of high altitude training. J Med Invest 2012;59:10210.

Consolazio CF, Matoush LO, Johnson HL, Krzywicki HJ, Daws TA, GJ Isaac. Effects of high- carbohydrate diets on performance and clinical symptomatology after rapid ascent to high altitude. Fed Proc 1969;28:937–43.

Brugarolas J, Lei K, Hurley RL et al. Regulation of mTOR function in response to hypoxia by REDD1 and the TSC1/TSC2 tumor suppressor complex. Genes Dev 2004;18:2893–904.

Witard OC, Jackman SR, Breen L, Smith K, Selby A, Tipton KD. Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise. Am J Clin Nutr 2014;99:86–95.

Koopman R, Verdijk L, Manders RJ, et al. Co-ingestion of protein and leucine stimulates muscle protein synthesis rates to the same extent in young and elderly lean men. Am J Clin Nutr 2006;84:623–32.

Rai RM, Malhotra MS, Dimri GP, Sampathkumar T. Utilization of different quantities of fat at high altitude. Am J Clin Nutr 1975;28:242–5.

Chung-Yu Chen, Chien-Wen Hou, Jeffrey R Bernard, Chiu-Chou Chen, Ta-Cheng Hung, Lu-Ling Cheng, Yi-Hung Liao, Chia-Hua Kuo. Rhodiola crenulata- and Cordyceps sinensis-based supplement boosts aerobic exercise performance after short-term high altitude training. High Alt Med Biol 2014 Sep;15(3):371-9.

Wolfarth B. A three-week traditional altitude training increases hemoglobin mass and red cell volume in elite bi-athlon athletes. Int J Sports Med 26:350–355.

Gore CJ, Sharpe K, Garvican-Lewis LA, Saunders PU, Hum-berstone CE, Robertson EY, Wachsmuth NB, Clark SA, McLean BD, Friedmann-Bette B, Neya M, Pottgiesser T, Schumacher YO, and Schmidt WF. (2013). Altitude training and haemoglobin mass from the optimised carbon monoxide rebreathing method determined by a meta-analysis. Br J Sports Med 47:i31–39.

Kelly GS. (2001). Rhodiola rosea: A possible plant adaptogen. Altern Med Rev 6:293–302.

Koh JH, Kim KM, Kim JM, Song JC, and Suh HJ. (2003). Antifatigue and antistress effect of the hot-water fraction from mycelia of Cordyceps sinensis. Biol Pharm Bull 26:691–694.

Chiou WF, Chang PC, Chou CJ, and Chen CF. (2000). Protein constituent contributes to the hypotensive and vasorelaxant activities of Cordyceps sinensis. Life Sci 66:1369–1376.

Lang JA, Krajek AC, Schwartz KS, Rand JE. Oral L-Tyrosine Supplementation Improves Core Temperature Maintenance in Older Adults. Med Sci Sports Exerc. 2020 Apr;52(4):928-934.