Adapting to a new training environment to improve performance has been practised by the pro’s for the past 40+
years. Professional athletes often spend weeks away at training camps, in specific locations designed to maximise performance potential.
For these athletes there are two opportunities which are often practised, training up high (altitude) and training in the sunshine (heat).
This article will briefly explore both methods and suggest why training in the heat is becoming more popular with both elite and age-group athletes alike.
As you are probably aware, the most commonly known method of adaptation training is at altitude. Here the oxygen level in the air is considerably lower, the decreased amount of oxygen in high altitudes stimulates the body into the production of the hormone erythropoietin (EPO) made in the kidneys. EPO then triggers the production of more red blood cells to transport sufficient oxygen to make up the deficiencies at altitude. More oxygen delivery to the muscles can increase aerobic capacity and thus endurance performance is improved. There is a widespread acceptance that altitude training improves performance both at altitude and at sea-level. So to maximise performance get training in the mountains! Simple, right? Well not exactly….
Previous theories on altitude training have been challenged, showing limitations to the old classic paradigm. Recently the England football team were criticised for using high altitude training following their failure at the 2010 World Cup. In the same year of England’s failure an interesting study from the University of Oregon on the benefits of heat training was published, turning more than a few heads (more on this later). This has sparked sports scientists into studying the benefits of heat training on performance. Many athletes are spending time in hot conditions to prepare for their upcoming event. So what is all the hype about? Why are more and more athletes looking to train in the heat?
Training in the heat incurs several physiological adaptations, known as heat acclimation. One of the primary adaptations to heat acclimation is an increase in blood plasma volume. Just as altitude stimulates your body to produce more red blood cells, heat stress stimulates your body to produce more blood plasma. A higher plasma volume enhances circulation, which improves the delivery of oxygen to muscles. The result is a greater cardiac output, and higher VO2max at a given effort level, enhancing endurance performance. So we know both heat training and altitude training cause physiological adaptations which can improve exercise performance. So why is heat training an alternative or even a superior option to altitude training!?
Time Taken to Adapt
One of the most practical advantages of heat training is the time taken to adapt. Heat acclimation has been shown to occur in as little as 5-7 days (Pandolf, 1997) with full adaptation to normothermic performance in 10 days (Lorenzo 2010). On the other side, in order to see favourable adaptation to altitude, you will need ideally 3-4 weeks, depending on the duration and intensity of daily exposure (Garvican 2012). Less time to see benefits mean less time spent away from family and work. As an age group athlete with a family and full-time job, getting away for 5-7 days is much more reasonable than 3-4 weeks!
Responders vs Non-Responders
Physiological responses to altitude training vary considerably between individuals (Martin, 2010). It is well known amongst the elite that there are ‘responders and non-responders’ to altitude training. Harsh but true, that some people just do not effectively respond to training at altitude. For the age group athletes (who unlike the elite do not have access to scientific testing to identify responses) it becomes a lottery whether you will gain the necessary adaptations to altitude training to improve performance. Very recent research indicates that the high variability (responders and non-responders) in acute altitude responses indicates a genetic component that might influence adaptation (Masschelein 2015). To explore whether heat training has a similar genetic component, a novel study is currently in the process of using the same sets of twins for heat acclimation. This exciting study will aim to identify the responses of heat acclimation and whether a genetic component exists.
It has long been known that heat acclimation can improve performance in hot conditions (Pandolf 1988; Sawka 1996). Recently, a University of Oregon study in 2010 had trained cyclists do 10 days of heat acclimation – 100 minutes of exercise in the heat each day – and saw a 5% jump in VO2max measured in cool conditions by the end of study. In other words, heat acclimation doesn’t just make you better at dealing with heat; it makes you better, period. The researchers suggested that athletes could use this type of protocol just like they use altitude training camps, as a short-term intervention to improve performance. Training camp in the sunshine, for any race conditions!? Surely this is too good to be true!?
A recent scientific review confirmed that there is now growing evidence for the benefits of heat training on performance in both hot and cool conditions (Chalmers, Esterman 2014), suggesting a realistic and maybe superior alternative to altitude training. A New Zealand study published in 2012 used elite rowers, exercising just five days, 90 minutes per day. The rowers were in a room at 40 C and 60% humidity, and they rowed at an intensity just sufficient to keep their core temperature at a “modest” overheating level of 38.5 C. The training itself wasn’t particularly hard: the goal was to overheat the rowers, not overwork them, and the 5-day acclimation period started two weeks before a major championship competition. The result: a 1.5% increase in 2,000m rowing performance.
The important message to take home is when you are looking to prepare for an event, consider how you can optimise your preparation. If you want to maximise performance for your next event, training in the heat might be the ideal preparation for you.
TRAINING AT ALTITUDE (SIMULATED / ACTUAL)
TRAINING IN THE HEAT (THERMOREGULATION)
What are the current recommendations?
- Optimal altitude range 2000 to 2500m (Arizona 2134m)
- 21-28 days exposure required
- Minimum >12-18 hrs per day (18-22hrs ave)
- Exercise oxygen saturation <80%
- Simulated hypoxic training (2350m / 14% O2)
- Temp >36˚C / Humidity >50%
- 7-14 days exposure
- 90-100 min per day (10 days in a row)
- 90min every 3rd day (30 days exposure)
- Exercise intensity approx 50% VO2 max
What are the reported benefits?
- Erythropoiesis (↑ EPO)
- ↑Red blood cell count and mass / haemoglobin
- ↑lactate clearance or ↓lactate production
- Improved fitness (aerobic & anaerobic)
- ↑O2 to muscle / ↑lactate buffering
- Benefits maintained 12-28 days(variable)
- ↑Plasma volume (3-6 days)
- ↓HR during exercise (3-6 days)
- ↓Loss of salt in sweat (5-10 days)
- ↑Sweat sensitivity (sweat sooner)
- ↑blood flow to skin (↑cooling effect)
- ↑ endurance(aerobic & anaerobic)
- Benefits maintained 10-28 days
How does this help performance?
- Improved Aerobic performance / cardiovascular fitness
- ↑oxygen to muscle = ↑ aerobic capacity
- Improved repeated high intensity effort ability
- ↑fat loss
- ↑recovery rate / rehabilitation
- ↑Oxygen to muscle = ↑ aerobic capacity
- Improved cardiovascular efficiency
- Maintained electrolyte balance
- ↑body internal cooling effect
- ↑glycogen sparing = ↑high intensity ex
What are the disadvantages or risks?
- Responders and non-responders (doesn’t work for everyone
- Altitude (mountain) sickness
- Training intensity may ↓ at altitude
- 25% greater energy demands vs sea level
- ? Impact on the immune system / ? risk of illness
- Heat illness if do too much too soon
- ↑Dehydration risk during training
- Cumulative dehydration risk during week
- Need right temp and humidity to work
- Physiological adaptation with ↓ training volume
- Integrated for fitness ‘Top Ups’ and ↓skinfolds
- Used in rehab to aid with return to fitness
- Implementation into individual training as appropriate
- Natural climate for performance
- Natural maintenance of Alt benefits
- Acclimatisation provides adv in comp
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