As if the odds were not already heavily stacked against Bermuda in their Concacaf Nations League encounter against Mexico, they will also face the enormous difficulty of playing at high altitude.With the Estadio Azteca, the home of Mexico’s national team, hosting an NFL match between the Kansas City Chiefs and the Los Angeles Rams on Monday, Bermuda’s final League A group game will be held in Toluca, a city sitting at an altitude of 2,680 metres above sea level.In addition to devising a plan to shackle the Gold Cup champions, who are ranked twelfth in the world, Bermuda’s coaches and support staff have also had to formulate a strategy to cope with the altitude factor.Not only does the ball fly far quicker through the thinner air, a nightmare for goalkeepers, making defending deep a dangerous tactic against a side with the shooting accuracy of Mexico, the lack of oxygen can severely limit an unacclimatised player’s athletic capacity.It is safe to say Bermuda will not be acclimatised.It takes three weeks to adjust to the demands of altitude; that is 21 days Bermuda do not have, given that a sizeable portion of their squad are based overseas, coupled with the Fifa international window being seven to ten days.It is for that very reason the team have chosen to fly to Toluca on the eve of the game in an effort to minimise the exposure to the unforgiving conditions.Since Tuesday they have been based in Frisco, Texas, which has the same time zone as Toluca and is where they met Costa Rica at the Gold Cup last summer. They then head to St Croix, US Virgin Islands, to play Major League Soccer side DC United in a friendly tomorrow.As well as seeking advice from a sports medicine consultant with specific knowledge of altitude, Bermuda have simply focused on “controlling the controllables” during the build-up to Tuesday’s game, according to team physio Craig Brown.“The first thing is that the oxygen levels are reduced by about two per cent, which means our players are going to have challenges with their breathing and ability to sprint and run for long periods of time,” Brown said.“The players will probably lose up to 25 per cent of their vo2 max, which is our aerobic capacity. “Another concern is that science shows that 10 to 20 per cent of people can get affected by acute mountain sickness, which can cause nausea, loss of appetite, sleep deprivation, headaches and dehydration.“In terms what we can do and what we can control, it’s very difficult because we don’t have the infrastructure in Bermuda and are working within budget constraints.”Given that holding cardio sessions in a hypoxic chamber is out of the question — only a handful of Premier League clubs have such a facility — Bermuda have had to adopt a practical approach to their preparations.“We advised the players to switch to a high protein diet in an effort to lose a few pounds, which will help improve their vo2 max,” Brown added. “We’ve also asked them to increase their high-intensity training and add more garlic to their diet to help thin the blood. It’s something we tried with the national cricket team when they played at high altitude [in Pretoria and Nairobi] about ten years ago.“The science behind it isn’tthat great, but the Sherpas in the Himalayas swear by it.”Genetic factors seem to determine how each player will react when playing at high altitude and Brown insists that ensuring the health and safety of each squad member is of utmost importance.“We’ve looked into where the nearest hospital is [to the Nemesio Diez Stadium Stadium] in case of emergency and have also taken into consideration having oxygen on site for the players.“We will be doing regular urine-specific gravity tests to measure the players’ hydration, which is another real concern at high altitude.“We use a product called SOS Rehydrate to enhance hydration and reduce muscle cramping, a fantastic supplement that we add to the water, as water alone doesn’t have enough minerals and electrolytes to help muscular contractions.”History shows that acclimatised teams hold the trump card when playing in altitude against lowland opposition.So much so that Fifa introduced a ban on international matches at more than 2,700 metres above sea level in 2007, citing concerns about players’ health and possible distortion of competition.That ban was lifted a year later after protests from Andean nations such as Bolivia, Ecuador and Peru, understandably keen to preserve their geographic advantage.Kyle Lightbourne, the Bermuda coach, never had to contend with the challenges of playing at altitude during his career but believes it is part and parcel of competing at a higher international level.“We’ve followed the guidelines of our science department; that’s the best way to go about it,” Lightbourne said.“When Mexico came to Bermuda, they arrived the day before the match [a 5-1 win for Mexico last month]. There were reasons behind that, because just as we will struggle with altitude, they might struggle with humidity.“We know it’s going to be a challenge. We sent representatives to Toluca, to the stadium, to the hotel, and the feedback was that it’s very difficult to breathe.“Again, this is part of international football and we have to make adjustments. There’s no sense crying over it; we have to deal with it.”