From Fitness to Risk: How High-Intensity Workouts Can Affect Your Kidney Health

Have you ever felt the exhilarating rush of pushing your limits in a high-intensity workout, only to be hit with unexpected fatigue or discomfort? You're not alone. For many athletes and fitness enthusiasts, the intense challenge of High-Intensity Interval Resistance Training (HIIRT) can be both rewarding and taxing. While these workouts can improve cardiovascular health and muscle performance, they may pose unexpected risks to the bladder and kidneys. We spoke to our expert Dr K Kranthi Kumar, Consultant Nephrologist, Asian Institute of Nephrology and Urology, Hyderabad, who shed light on how high-intensity sports can impact kidney health and how you can protect yourself.

Benefits and Mechanics of HIIRT

High-intensity interval resistance training (HIIRT) has become a popular exercise regimen due to its effectiveness in delivering results through brief sessions. "Engaging in HIIT every week enhances muscle oxidative capacity, boosts both aerobic and anaerobic fitness, lowers arterial blood pressure, aids in weight loss for obese individuals, and enhances glucose regulation and insulin sensitivity in people with type 2 diabetes," said Dr Kumar.

According to the International Journal of Environmental Research and Public Health, HIIRT involves repeated, brief bursts of intense activity performed at a “near maximal” or “all-out” effort, typically reaching ≥90% of maximal oxygen uptake or >75% of maximal power. These intense periods are interspersed with rest or lower-intensity exercises.

Also Read: High-Intensity Training For Six Months Offers Health Benefits For 5 Years: Try These HIIT Exercises

Potential Risks: Muscle Damage and Renal Injury

Despite its benefits, HIIRT can pose risks, particularly related to muscle damage and renal injury. One significant concern is rhabdomyolysis, a rare but serious condition that can result from high-intensity exercise.

Rhabdomyolysis occurs when muscle tissue breaks down and releases its contents into the bloodstream. These substances can be harmful to the kidneys, potentially leading to Acute Kidney Injury (AKI), said Dr Kumar. Key aspects of rhabdomyolysis include:

• Muscle Breakdown:  The breakdown of muscle cells releases myoglobin and other substances into the bloodstream
• Kidney Damage: Myoglobin and other byproducts can damage kidney cells, potentially leading to impaired kidney function

According to the StatPearls, rhabdomyolysis is a leading cause of acute renal failure. When detected early, the outcome of acute kidney injury caused by rhabdomyolysis is generally favourable. In the United States, about 25,000 cases of rhabdomyolysis are reported annually, with the incidence of acute kidney injury occurring in approximately 5-30% of these cases.

Also Read: Stress And Sleep: How Lifestyle Factors Influence Renal Function

Risk Factors for Kidney Damage

Dr Kumar listed the factors increasing the risk of developing kidney damage from HIIRT:

• Dehydration:  Inadequate fluid intake can exacerbate kidney stress and increase the risk of injury
• Age: Individuals over 40 are more susceptible to kidney issues during high-intensity exercise
• Genetic Myopathies: Pre-existing muscle diseases can heighten the risk of rhabdomyolysis
• Painkillers and Alcohol: The use of these substances can increase the likelihood of kidney damage
• Recreational Drugs: Their use can compound the risk of both muscle damage and renal injury
• Environmental Conditions: High temperatures can intensify the risk of dehydration and subsequent kidney stress
• Infectious Illness: Illnesses can increase vulnerability to kidney damage
• Exercise Intensity: Higher-intensity workouts can elevate the risk of injury, especially if not managed properly

Recommendations for Safe Practice

To minimise these risks, it is crucial for those engaging in HIIRT to adhere to these safety guidelines shared by the expert:

• Professional Supervision: Engage in HIIRT under the guidance of a qualified professional to ensure proper technique and safety
• Gradual Progression: Introduce high-intensity exercises gradually to avoid overloading the body and prevent injuries
• Avoid Dehydration: Maintain adequate fluid intake before, during, and after workouts to support kidney function
• Limit Alcohol and Painkillers: Reduce consumption of alcohol and pain medications, which can exacerbate kidney stress
• Monitor Environmental Conditions: Be mindful of high temperatures and adjust your exercise routine accordingly to avoid overheating and dehydration

[Disclaimer: This article contains information provided by an expert and is for informational purposes only. Hence, we advise you to consult your own professional if you are dealing with any health issues to avoid complications.]