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21/11/13

The Competitive Edge

A few months ago I took on the role of General Manager for a new venture company called “Altitude Services” see: www.altitudeservices.com.au.

As an exercise physiologist who’s played in this space for the best part of 15-20 years from a scientific, coaching and personal training perspective, I’ve known the benefits associated with altitude exposure whilst not huge are certainly significant – particularly at the top end. “Altitude training” certainly won’t turn a donkey into a world beating Thoroughbred, however if you’re already on the edge of greatness, nipping at the heels of the leaders in your age group, wanting to take that next step, already exhausted all other options (i.e. Training and recovering well, have your nutrition down pat, optimized your equipment, are at your optimal race weight, etc.) then altitude training can be yet another weapon in your arsenal of competitive tools.

It isn’t a coincidence that not so long ago in the athletic world every world record from 800m to the marathon was held by an athlete that was either born and trained at altitude or used some form of altitude simulation routinely as part of their training regimen. Locations such as Boulder, St Moritz, Flagstaff, etc. have become synonymous with endurance sport training.

So what happens to the body at altitude?

The physiological adaptation to altitude exposure goes through two distinct phases :

  1. Upon initial altitude exposure (days 1 to 7-10) there is (i) an increase rate and depth or respiration and (ii) increased cardiac output (both heart rate and stroke volume). During this period training loads should be kept low and aerobic as the athlete is experiencing significant physiological loading. The only quality work should be short (10-15 second) efforts rather than longer sustained lactic sessions.
  2. In the second phase of altitude adaptation (days 7-24-30), as the athletes body starts to acclimate to altitude stress, heart rate and respiration decrease back to normal/pre-exposure levels as other bio-physiological changes kick in (e.g. Increases in red cell mass, increases in aerobic enzymes, increased mitochondria concentrations, capillary density, myoglobin concentrations, etc.). In humans this is often shown initially as an increase in red cell concentration which may then (in some athletes) return to normal levels as plasma volume increases – as is the case with heat exposure.

It is during this second adaptation phase that training loads can generally be progressively increased back towards normal training loads.

The above is typical of a reasonably well trained athlete going from sea level to train at altitude.

Living for sustained periods of time at altitude, has in some circumstances, actually proven to be detrimental to performance as athletes have (i) been unable to train hard and fast enough to maintain top end speed and (ii) with sustained altitude exposure the body can become “catabolic” actually eating into its own muscle mass and consequently decreasing power to weight ratio.

It was for these reasons, more than a decade ago that American Professor Benjamin Levine proposed the “live high, train low model” of altitude training whereby athletes lived at altitude but trained at sea-level. This landmark study produced significant performance improvements in 5km performance times for a group of well trained, sub-elite runners.

The problem is/was not everyone (a) had access to a mountain, (b) had the time to drive up and down or (c) could afford to relocate in order to train in this manner.

Simulated altitude training was born.

From the early days of the CAT Hatch – a Perspex vessel into which an athlete slid, air was literally sucked out to simulate a specified altitude. Whilst effective from a training perspective, these chambers proved to be impractical. For example, if you wanted to go to the loo during the night you either had to wee into a bottle in the chamber or vent the chamber go to the toilet and then get back in and bring the vacuum system in the chamber back to the levels you wanted it at.

Soon after the CAT Hatch system we saw the evolution of the altitude tents – whereby a small generator pumped hypoxic gas into a tent at a rate of about 120 litres per minute whilst you slept. These systems allow you to vary the O2 concentration of the air at normal air pressures – lowering the risk of altitude related illnesses due to “hypobaria” – low pressure akin to what is experienced when going up a mountain. These systems have proven popular and persist to this day. These hypoxic generators can also be removed from the sleeping tent, married directly to a face mask and the athlete can train in their preferred exercise modality (e.g. Rowing, swimming – yes, they have even placed domes over lanes to trap the hypoxic air whilst swimmers train in these environments, cycling, running, etc.)

Where are we today and what does the future hold in this regards?

Currently the price of altitude simulators is decreasing – although with some suppliers you wouldn’t know it! In some locations around the world hotels are getting into the athletic market by providing altitude rooms for athletes to live in whilst they are holidaying on training camps. The company I’m involved in is one of the first in the world to successfully infiltrate the Thoroughbred racing market with altitude stalls and training facilities throughout Australia with doors opening into South Africa and the Middle East. One of the major controlling factors being the ability to control the “dosage” of hypoxia via pulse oximetry – which measures the oxygen concentration in the blood during the hypoxic exposure. Two athletes – be they human, equine, camel, etc. – exposed to precisely the same hypoxic conditions (i.e. Oxygen levels and duration of exposure) can respond in completely different manners. One can be quickly overwhelmed by the hypoxia, for the second the hypoxia may have little/no impact – by measuring blood oxygen saturation (SAO2) the trainer, athlete, coach, sports scientist can better refine the hypoxic training regimen on an athlete by athlete basis.

Some key points to remember :

  • Altitude training is not a one size fits all. Altitude training (at least with human athletes) is beneficial in about 85% of cases, some athletes simply don’t cope and go backwards. Pulse oximetry helps with personalizing altitude exposure.
  • Extended periods of altitude exposure can result in muscle wastage – hence the importance of regularly weighing yourself if you’re at altitude for an extended period of time.
  • Altitude training is dehydrating. You breathe deeper and harder drying out your airways. If you’re in a simulated altitude the environment is also air conditioned which exasperates this problem.
  • Altitude training effects persist post-exposure for 3-4 weeks but decrease progressively.
  • Aside from the aerobic benefits it is thought that altitude also has a beneficial impact on lactic acid buffering (i.e. Human athletes seen to have the greatest benefit have been rowers – 6-8 minute maximal efforts – significant contributions from both aerobic/anaerobic systems).
  • Counter-intuitively, athletes sometimes struggle more at altitude than non-athletes. Athletes are used (due to training) to often being “hypoxic” whereas non-athletes when exposed to hypoxia increase respiration, etc. immediately – some athletes don’t. Therefore some athletes suffer more readily with altitude exposure from a blunted response to the need to breathe more than do non-athletes. Again regularly monitoring your oxygen saturation levels can be valuable here.
  • Males seem to adapt more quickly to altitude than do females.
  • When adapting to altitude increase your intake of carbohydrate.
  • Many athletes complain of “altitude hangover” during the acclimation period.  Literally feeling like they have a hangover – which leads to the following point.
  • Typically human athletes exposed to altitude have intensive flat spots of fatigue through weeks 2, 3 or 4 depending on the individual athlete, training load, maturity, prior altitude exposure, etc. Normally 2-3 days down from altitude coupled with lighter training loads are enough to turn this around.
  • When using the sleep high/train low model ensure the athlete has at least two hours back at sea level before commencing a training session – particularly an intense training session and at least one hour at sea-level (for adequate recovery) before going back to altitude to rest or sleep.

Altitude training is still a work in progress. The AIS has built its own “nitrogen room” recognizing there is a modest (but valuable) ROI for elite athletes. The message for Jack and Jill Average – get everything else sorted and then if you’re looking for that little bit extra explore altitude training as a viable option to improve your endurance and competitive edge.