Just a few days ago i was talking about cooling / bring sufficient water on the bike........
And you know, over here in SG, this can really happen very quickly.
Yes, dehydration in athletes is a significant
contributing factor to an increased risk of cardiac events. While dehydration alone is not the primary cause of sudden cardiac death in most cases, it places substantial strain on the cardiovascular system that can trigger a fatal arrhythmia in individuals with an underlying, often silent, heart condition.
How Dehydration Increases Cardiac Risk
Dehydration exacerbates the physiological stress of intense exercise through several mechanisms:
- Reduced Blood Volume: Dehydration decreases blood volume, forcing the heart to work harder and faster to pump sufficient oxygenated blood to muscles and organs. This increased heart rate (tachycardia) and strain can lead to hypotension (low blood pressure) and, in extreme cases, shock or cardiac arrest.
- Electrolyte Imbalances: Sweating causes a loss of essential electrolytes like sodium, potassium, and magnesium, which are crucial for the heart's electrical signals and maintaining a steady rhythm. Disruptions in this balance can lead to dangerous, irregular heartbeats (arrhythmias), which are a common trigger for sudden cardiac arrest.
- Increased Blood Viscosity: Dehydrated blood becomes thicker or more viscous, which increases the likelihood of blood clot formation. This heightens the risk of a heart attack or stroke.
- Heat-Related Stress: Dehydration impairs the body's ability to cool itself through sweating, leading to a rise in core body temperature (hyperthermia). The combination of dehydration and hyperthermia creates significant cardiovascular strain, making it harder for the heart to maintain adequate blood pressure and cardiac output.