It releases chemicals in the brain called endorphins, which boost your mood.

When you exercise, your body releases chemicals called endorphins.

It triggers the release of hormones called endorphins into your brain.

Running raises our spirits because of the "feel good" natural chemicals, called endorphins, which flood the brain.

The placebo effect may be the result of "feel good" hormones called endorphins that are released by the brain in response to treatment.

Scientists have long theorised that these natural chemicals, called endorphins, may cause "runners' high".

Some researchers have found evidence that music stimulates the body to produce natural pain-killing substances called endorphins.

When you work out, your body releases chemical messengers called endorphins, which make you feel good.

When you exercise, your body produces "feel good" substances called endorphins.

Another theory is that stimulating the nerves may help the body produce natural painkillers called endorphins.