Why Peru's Health Ministry Is Warning Exercisers About Extreme Heat

Peru's Ministry of Health (Minsa) has warned that exercising under intense sun does more than risk dehydration: it also places real strain on the heart. According to the ministry's advisory, physical activity in extreme heat increases the risk of heart attacks, arrhythmias and other cardiovascular complications, particularly for people with pre-existing conditions.

The warning is detailed by cardiologist Alber Terrones Zamora of Lima's Hospital Carlos Lanfranco La Hoz. When someone exercises in temperatures above 30-35°C, the body activates mechanisms to regulate its core temperature, adding a heavy load to the cardiovascular system. The specialist said that overload reduces blood flow and affects cardiac function, raising the risk of a heart attack or arrhythmias.

The threat is greatest for people with hypertension, diabetes or a history of heart attacks and other cardiovascular disease, as well as for older adults. Terrones Zamora urged anyone who feels persistent dizziness, blurred vision or oppressive chest pain to stop exercising immediately, since these can be signs of a medical emergency. Minsa also recommends preventive check-ups before taking up high-exertion sports and points the public to the free 113 Salud helpline for consultations.

The Heart-Strain Mechanism and Who Is Most at Risk

Why heat makes the heart work harder

The mechanism behind the warning is a double demand on the body. Exercise itself requires more blood flow to muscles, while intense heat pushes the body to shed warmth by directing blood toward the skin. Working against both pressures at once forces the heart to pump harder, and as blood is redistributed, other organs receive less. In practical terms, the specialist says, that reduced flow can destabilise heart function in vulnerable people — which is why dizziness, blurred vision and chest pain are treated as warning signs rather than discomfort to push through.

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Who carries the higher risk

The advisory is squarely aimed at exercisers who already carry a higher baseline cardiovascular load: people with hypertension, diabetes or a prior heart attack, and older adults. For these groups, added heat stress can be the difference between a routine training session and an acute cardiac event. What the ministry does not provide is a quantified risk figure — the warning describes the danger qualitatively. Read as a public health measure, its practical goal is to keep heat-related emergencies away from emergency rooms, although Minsa's statement does not discuss hospital impact.

A Practical Checklist for Safe Exercise in Extreme Heat

For readers who train outdoors in hot conditions, the ministry's advice translates into a short checklist:

  • Move high-exertion sessions out of the hottest hours and treat temperatures above 30-35°C — the threshold cited by cardiologist Alber Terrones Zamora — as a reason to reduce intensity.
  • Stop immediately, rather than powering through, if persistent dizziness, blurred vision or oppressive chest pain appear; the specialist describes these as potential signs of a medical emergency.
  • People with hypertension, diabetes, or a history of heart attacks — and older adults — should get a preventive medical check-up before starting high-exertion sports, per Minsa's recommendation.
  • For emergencies or health questions, use Peru's free 113 Salud helpline.