The Tribune

By DR KENT L BAZARD

Sports Medicine Physician

FOR athletes in The Bahamas, training in the heat is simply part of life. Whether it is a track athlete completing sprint sessions in the afternoon sun, a swimmer performing dryland conditioning, a baseball player spending hours on the field, or a basketball team practicing in a warm gymnasium, environmental heat becomes another training stimulus that the body must learn to manage.

Many athletes view the heat as the enemy. It makes workouts feel harder, causes fatigue to develop more quickly, and often reduces performance. Yet from a sports medicine perspective, heat is neither good nor bad.

Like resistance training or sprinting, heat is simply another physiological stressor. When applied appropriately, the body adapts remarkably well. When ignored or underestimated, it becomes a major contributor to fatigue, poor performance, and potentially life-threatening illness.

One of the first physiological changes that occurs during exercise in the heat is an increase in cardiovascular demand. As body temperature rises, the skin requires greater blood flow to dissipate heat through sweating and radiation.

At the same time, the working muscles continue demanding oxygen and nutrients. The heart is therefore forced to perform two critical jobs simultaneously: supporting muscular work while also cooling the body. Heart rate increases, even when exercise intensity remains unchanged, a phenomenon known as cardiovascular drift.

Athletes often notice that a pace or workload that normally feels comfortable suddenly feels much harder on a hot day. The reason is not simply dehydration; it is that the cardiovascular system is working significantly harder to maintain homeostasis.

Heat also alters energy metabolism. As core temperature increases, the body relies more heavily on carbohydrate metabolism and muscle glycogen. Glycogen stores are depleted more rapidly, accelerating fatigue during prolonged exercise. This helps explain why athletes who train or compete in hot environments often “hit the wall” earlier than expected, even when they believe they are adequately conditioned.

Proper carbohydrate intake before and during prolonged activity therefore becomes even more important under hot environmental conditions.

The nervous system is equally affected. Rising body temperature influences motor unit recruitment, nerve conduction, and central nervous system function. Research has demonstrated that hyperthermia contributes to central fatigue, where the brain voluntarily reduces motor drive to working muscles as a protective mechanism. In practical terms, athletes may notice slower reaction times, reduced power output, impaired coordination, and decreased decision-making ability before they ever feel completely exhausted. This is one reason technical errors often increase late in competitions held under extreme heat.

Fluid loss through sweating further complicates performance. Sweat is not simply water; it contains sodium, chloride, potassium, and other electrolytes essential for nerve conduction and muscle contraction. Excessive sweat losses reduce plasma volume, decreasing stroke volume and forcing the heart to beat faster to maintain cardiac output.

As dehydration progresses, the body’s ability to dissipate heat becomes impaired, further accelerating the rise in core temperature. Research suggests that fluid losses exceeding approximately two percent of body mass begin to impair endurance performance, cognitive function, and thermoregulation, although the exact threshold varies among individuals.

Fortunately, the human body is highly adaptable. One of the most fascinating concepts in exercise physiology is heat acclimatization. Following repeated exposure over approximately seven to 14 days, the body undergoes several measurable adaptations. Plasma volume expands, improving cardiovascular stability. Sweating begins earlier during exercise and becomes more efficient. Sweat becomes more dilute, conserving sodium.

Heart rate decreases at a given workload, while perceived exertion is reduced despite identical environmental conditions. Collectively, these changes allow athletes to tolerate heat more effectively and maintain higher performance levels.This principle has become standard practice among elite sporting organisations.

Athletes preparing for competitions in hot climates often undergo structured heat-acclimation protocols before major championships. The goal is not simply to survive the heat but to use physiological adaptation as a competitive advantage.

However, adaptation should never be confused with invincibility. Heat illness remains one of the most preventable medical emergencies in sport. Heat cramps, heat exhaustion, and exertional heat stroke exist along a spectrum of increasing severity. Heat stroke represents a true medical emergency characterised by central nervous system dysfunction and dangerously elevated core body temperature. Immediate recognition, rapid cooling, and emergency medical treatment are essential. Every coach working in The Bahamas should be familiar with the early warning signs of heat illness and have an emergency action plan in place.

Recovery becomes particularly important during periods of heavy training in the heat.

Replacing fluid losses requires more than simply drinking water after practice. Athletes should restore fluids, sodium, carbohydrates, and protein to support both rehydration and muscle recovery. Sleep quality also becomes increasingly important, as much of the body’s physiological adaptation occurs during overnight recovery. Athletes who consistently under-recover often begin the next training session already carrying a hydration deficit and accumulated fatigue.

Not every athlete responds to heat in the same way. Body composition, fitness level, acclimatization status, genetics, age, medications, and even previous illness influence heat tolerance. This is why training programmes should be individualised rather than assuming every athlete can tolerate identical workloads under identical environmental conditions.

At Empire Sports Medicine & Performance, environmental conditions are considered another training variable, just like speed, volume, or resistance.

Athletes recovering from injury, returning after illness, or preparing for major competition may require adjustments in workload, hydration strategies, recovery protocols, and nutritional planning depending on heat exposure.

Monitoring fatigue, recovery, and performance allows training to remain productive while reducing unnecessary risk.

Perhaps the greatest misconception is that struggling in the heat means an athlete is mentally weak or poorly conditioned.

More often, it reflects normal human physiology responding to an extraordinary environmental challenge.

The athlete who understands how heat affects the body can make better decisions about pacing, hydration, nutrition, and recovery.

More importantly, they can use the environment to build adaptation rather than allowing it to become an obstacle.

Living and training in The Bahamas gives our athletes something many competitors around the world must artificially create.

Used wisely, our climate can become one of our greatest training tools. The goal is not simply to endure the heat.

The goal is to understand it, adapt to it, and ultimately perform because of it rather than in spite of it.