HomeAnswersCardiologycardio exercisesMay I know the risks of high-intensity cardio exercise?

What are the risks of high-intensity cardio exercise?


The following is an actual conversation between an iCliniq user and a doctor that has been reviewed and published as a Premium Q&A.

Medically reviewed by

Dr. K. Shobana

Published At June 20, 2018
Reviewed AtFebruary 20, 2024

Patient's Query

Hello doctor,

I am a healthy 36-year-old. I run several times a week, often sprinting up hills for two to three minutes. In the past three years, I have had a few minor cardio-related symptoms, which I had checked out because I am motivated to stay in top physical condition. These include dizziness (drop in blood pressure) when standing up suddenly, feeling of shortness of breath during minor physical exertion (for example climbing stairs). That seemed out of character for my general level of fitness and a minor episode of palpitations that resolved in a week or so (last year). I have had two thorough cardio workups in the past five years to look into these issues, including a 24 hour Holter monitor, EKGs, and two cardio treadmill stress tests. Two cardiologists have told me my cardiovascular system is in excellent shape and they cannot find anything wrong. They seemed quite impressed I made the full 21 m on the treadmill. I have no current cardio issues. My question is this: what are the risks of intense cardio exercise? Basically, what are the risks if I try to sprint up a mountain? I have read about the dangers of long periods of running, one hour or more, but do not really see anything about the risks of dropping dead from sprinting too hard too long.


Welcome to icliniq.com.

Exercising regularly is a good thing to keep ourselves healthy. If you are a trained athlete and exercising under the guidance of an expert for intense cardio, exercise risk will be minimal. Your expert will design a workup that will suit you, like duration of the session, the frequency of the session, and adequate rest periods between workup. So, the risk of intense cardio exercise will be minimal if it is planned properly according to your fitness levels. Coming to your second question, if you sprint up a mountain with an adequate recovery period in between, the risk will be less. If you do not allow adequate recovery period, you may get symptoms related to muscular fatigue and dehydration. If you go high up the mountain (at 5000 to 8000 feet), there will be less oxygen availability and if you are not accustomed to such conditions of low levels of oxygen you may develop acute mountain sickness and then exercising will be harmful. If you are accustomed to low levels of oxygen, moderate-intensity exercise may be advisable under expert guidance.Hope this helps.

Patient's Query

Thank you doctor,

To clarify, the running route I was thinking of will be at a low elevation, under 3000 feet. It is foothills and not real mountains. Therefore, I do not think elevation sickness will be a concern here. My only concern is with maximizing my heart rate for 20+ minutes. I have previously sprinted for 1 mile (6 minutes) but never persisted at or near my maximum heart rate for longer than that. Are there risks in staying at 99 % of my maximum heart rate for, say, 10 to 20 minutes? How about 30? Or 60 minutes? I would bring a friend with me on this run to look after me but would not be under the supervision of a doctor or trainer.


Welcome back to icliniq.com.

As per ACSM (American college of sports medicine), the maximum duration of a high-intensity workout is eight minutes with adequate recovery periods totaling to 20 to 60 minutes each session (roughly four exercises with equal rest) three days a week. Overexertion beyond your physiological limits will definitely be harmful. Each individual is different with different capacities. So, if you are not able to go beyond six minutes, I will not advise you go beyond it. Thanks. Hope this helps.

Same symptoms don't mean you have the same problem. Consult a doctor now!

Dr. Sapkal Ganeshrao Patilba
Dr. Sapkal Ganeshrao Patilba


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