Heat Stroke May Be Bigger Threat Than Heart Attack for Runners

Heat stroke killed more runners than heart problems in recent study

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Many long-distance runners are at risk of death from heart problems during races. But athletes and doctors may need to turn their attention to another risk factor.

A recent study found that runners were 10 times more likely to experience heat stroke than heart-related medical events during long-distance races.

"Drink plenty of water and avoid the heat while exercising."

This study was conducted by Lior Yankelson, MD, PhD, from the Department of Cardiology of the Tel Aviv Sourasky Medical Center and Sackler School of Medicine at Tel Aviv University in Israel, and colleagues.

The study included 137,580 runners who ran in any of the 14 popular long-distance races in Tel Aviv between March 2007 and November 2013. They ranged from highly trained to amateur athletes.

The researchers identified the number of runners by using online records that recorded how many people crossed the finish line in each race. They also reviewed data on deaths and hospitalizations for each race.

The findings showed that only two participants were hospitalized for heart-related events — neither of which were deadly.

However, researchers discovered that 21 participants were hospitalized for heat stroke. Among those hospitalized for heat stroke, two died and 12 had life-threatening cases.

The sport-related death rate in this study was 1 out of 69,000 athletes, the study authors reported.

The authors explained that, under Israeli sports law, athletes who organize into teams or associations are required to get an electrocardiogram (ECG) — which measures the electric activity of the heart — before participating in sports. However, this is not required for solo runners in public races.

Runners in public races are only required to submit a personal statement saying that they are in good health.

The researchers surveyed 513 runners from the 2013 races to see how many had gotten an ECG and/or had an in-depth medical screening.

Dr. Yankelson and team also found that only 36 percent of the 513 runners surveyed at the 2013 race had had an ECG in the year before the race. Only 46 percent had received an ECG within the five years before the race. This means that the likelihood of runners with cardiac problems being screened out ahead of time was small, and that the data was accurate.

"This research shows that heat stroke is a real threat to marathon and long-distance runners; however, there are no clinical studies of potential strategies to prevent heat stroke during these types of events," said co-author Sami Viskin, MD, from the Department of Cardiology at Tel Aviv Medical Center, in a press release. "It's important that clinicians educate runners on the ways to minimize their risk of heat stroke, including allowing 10-14 days to adjust to a warm climate, discouraging running if a person is ill or was recently ill because a pre-existing fever impairs the body's ability to dissipate additional heat stress, and developing better methods of monitoring body core temperature during physical activity."

The study authors noted that the research could have been limited because some of the runners were screened before the races. If any heart problems showed up, the athletes likely would not have run. But, the researchers reported, most of the runners did not undergo pre-screening because they were not running with official sports organizations.

This study was published online July 28 in the Journal of the American College of Cardiology. The authors disclosed no conflicts of interest.

Review Date: 
July 28, 2014
Last Updated:
July 30, 2014