Running suits most people. It does not suit everyone all of the time, and knowing when not to run is a skill worth learning early. This is the least glamorous article on this site and probably the most useful.
Talk to a doctor first if any of these apply
These are not reasons you can never run. They are reasons to get cleared by a doctor before you start, so that you start in a way that is right for you.
- Known heart disease, an irregular heartbeat, or a heart condition in your family diagnosed at a young age
- Chest pain, pressure or tightness during exertion — at any age, this is a see-someone-now symptom, not a push-through-it one
- Fainting, blackouts or unexplained dizziness on exertion
- Uncontrolled high blood pressure or diabetes that is not yet stable
- Pregnancy, or the first months after giving birth
- A recent operation, fracture or significant injury
- Diagnosed osteoporosis or a history of stress fractures
- Asthma that is not well controlled
If you are over 40, have been inactive for years, or are carrying significant extra weight, a check-up before you start is simply sensible. It is a short conversation, and it usually ends with a doctor telling you to go running.
Stop immediately and call an ambulance
These are not “get it checked next week” symptoms. In India the emergency numbers are 108 or 112.
- Chest pain, pressure or tightness — especially spreading into the jaw, neck, back or either arm. Stop, sit down, and call. Do not try to walk home, and do not drive yourself.
- Collapse, or anyone who becomes unresponsive. Call 108/112 and start chest compressions if they are not breathing normally. Sudden cardiac arrest in a runner is rare, but survival depends almost entirely on how fast someone starts compressions.
- Confusion, disorientation, staggering or unusual aggression — in heat, this is exertional heat stroke until proven otherwise. See the heat section below.
- Severe breathlessness out of proportion to the effort, particularly if it comes on suddenly.
- Fainting, or feeling like you are about to.
Stop the run and get it looked at soon
Not an emergency, but do not run on it again until someone has looked:
- Sudden sharp pain in a joint or bone, especially if it makes you limp
- Pain in one specific point on a bone that gets worse as you run — the classic pattern of a stress fracture
Heat: the one that actually kills runners here
Gurugram runs past 43°C in May and June. Exertional heat stroke is a medical emergency, and the way most runners are taught to spot it is wrong.
The sign is the brain, not the skin. Runners are told heat stroke means you stop sweating. In exertional heat stroke the skin is usually still hot and sweaty. Waiting for dry skin wastes the time that matters. What to watch for is confusion, disorientation, aggression or unusual behaviour, staggering, or collapse.
If you suspect it: cool first, transport second. Two things a helper needs to know: do not use an ear, forehead or oral thermometer to rule this out — they are invalid here and read falsely low, so the device will reassure you when it should not. And cool to about 38.9°C and then stop, or roughly 10 to 15 minutes of immersion if you have no thermometer, because cooling past that causes hypothermia. Get them into shade, get clothing off, and cool them as aggressively as you can — cold water immersion is the most effective method, and iced towels over the whole body rotated constantly are the practical alternative. Call 108 or 112. Do not put a confused, collapsing runner in a car and drive across Gurugram traffic before starting to cool them.
And do not fix it by drinking more. The other heat-season danger is the opposite one: drinking far more than you sweat dilutes your blood sodium, which has killed endurance runners. Electrolyte tablets do not prevent it if you are over-drinking. The evidence-based instruction is simple — drink to thirst, not to a schedule. Gaining weight over a long run is the warning sign, not losing it.
Practically, in an Indian summer: move the run earlier, cut the distance, drop the intensity, and accept that some weeks are for the treadmill. Nobody has ever regretted skipping a tempo run in 42°C.
When to rest, even though you feel fine
Illness: the neck rule, and its one dangerous exception
Symptoms above the neck — a mild head cold, a blocked nose — and an easy run is usually fine. Symptoms below the neck, a fever, body aches or a chesty cough, and you rest.
Here is the reason that rule exists, which most versions of it leave out. Some viral infections can inflame the heart muscle — myocarditis — and hard exercise during an active viral illness makes that inflammation worse. Myocarditis is one of the leading causes of sudden cardiac death in athletes. That is what the rule is protecting you from, and it is why a fever is a hard stop rather than a judgement call.
Treat these as reasons to see a doctor before running again, not just to rest longer: new palpitations or a racing heart at rest, chest discomfort, breathlessness out of proportion to the effort, or unusual fatigue that persists after a viral illness has otherwise cleared. Those want a cardiac assessment.
Pain that changes how you move
Mild muscle soreness that eases as you warm up is normal. Pain that makes you limp, alter your stride, or that gets worse during the run, means stop. Pain that is still there the next morning means take at least a day and get it assessed if it persists past a week.
The signs you are doing too much
- Your easy pace feels hard for several days running
- Resting heart rate noticeably higher than usual
- Sleeping badly, unusually irritable, appetite off
- Getting every cold going round
- Motivation gone — often the first symptom, and the one people ignore
The fix is rarely dramatic: two or three easy days, or one full week at half the volume.
Rest is part of the training, not a gap in it
You do not get fitter during the run. You get fitter during the recovery afterwards, when the body repairs and rebuilds. A week off will not undo your fitness — measurable losses take two to three weeks. An injury run through will cost you far more than the week you were trying to save.