Someone tells you running will destroy your knees roughly every time you mention that you run. It is the most repeated piece of fitness folklore in Britain, and the data does not support it. When Alentorn-Geli and colleagues pooled 25 studies covering 125,810 people in 2017, hip and knee osteoarthritis turned up in 3.5% of recreational runners and 10.2% of people who did not run. Sitting still was the riskier option.

Here is what the benefits of running actually add up to, for your body and your head, and where the evidence is strong rather than merely popular.

The mortality benefits of running are the headline

Pedisic and colleagues pooled 14 studies in the British Journal of Sports Medicine in 2020: 232,149 people, 25,951 deaths, follow-ups running from 5.5 to 35 years. Runners had a 27% lower risk of dying from any cause, 30% lower from cardiovascular disease, and 23% lower from cancer.

The part worth reading twice is the dose. The meta-regression found no significant trend for weekly frequency, duration, pace or total volume. Running once a week carried most of the benefit. You do not need to be a marathoner to collect it.

What it does to your head

Running as a depression treatment is not a soft claim any more. Verhoeven and colleagues (2023) randomised 141 people with depression or anxiety to either an SSRI or outdoor running twice a week for 45 minutes, across 16 weeks. Remission rates came out level: 44.8% on antidepressants, 43.3% on running. The running group also improved on blood pressure, weight, waist circumference and lung function, while the medication group drifted the other way on those markers.

One honest caveat, and it matters. Only 52% of the running group completed the required sessions against 82% medication adherence. Running works if you actually do it, and doing it is the hard part. This is not a reason to stop your medication. It is a reason to add the runs.

The bits people get wrong

Runner’s high is not endorphins. Siebers and colleagues (2021) put 63 people through 45 minutes of running and found the euphoria survived intact when opioid receptors were blocked with naltrexone. Endocannabinoids rose regardless. Good science, and a decent excuse to stop calling it an endorphin rush.

Your bones like it. Running is an impact sport, and impact is the signal bone responds to. Swimming and cycling do plenty of good things. Loading your skeleton is not one of them.

Easy is where the benefit lives. Most of the cardiovascular adaptation comes from runs slow enough to hold a conversation. Hard sessions have a place, but they are the seasoning, not the meal.

What to actually do

Three runs a week, 20 to 30 minutes, slow enough to talk. That is the whole prescription for the health benefits above. Keep a rest day between them for the first few weeks so your tendons keep pace with your lungs.

Be honest about where you are starting. If you have not run in years, do not open with a 5K. Run a minute, walk two, and build from there.

Sharp or one-sided pain means stop and check it. A normal ache means keep going.

The knees argument is settled enough. The harder question is getting out of the door three times a week, and the only answer to that is starting small enough that it does not feel like a punishment.

Never run before? See How to Start Running: A Couch to 5K You Can Actually Finish.

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This is general fitness education, not medical advice. If you have a heart condition, a joint problem, or you are being treated for depression or anxiety, speak to your doctor before you change anything.