The happy runner is a nice example of how hard it maybe to experience happiness through running. The so-called runner’s high is available to everybody, if you manage to run long enough already. Most predictions put the threshold distance at about a 1 hour run. The reward for this effort is a special feeling that exceeds the pain or it makes you forget or supress the pain at least temporarily. Special reinforcements can be achieved through the big city runs in exciting places with thousands of people cheering you on. This has become a big business as well. Training for such an event might raise your feeling of happiness substantially. The chemistry of the endogenous production of stimulants of happiness in our body has been enlightened substantially in recent years (partly as doping control). Most of the brain active drugs our body can produce itself, although this involves a lot of physical and mental effort. The rewards are pretty healthy for most runners contributing to their basic level of happiness. Running outside, has contributed more to happiness for me more than the same exercise on a treadmil. Maybe, the environment is part of the happy runner’s high effect.