What is overtraining?
Overtraining is a state your body can get into if you are doing too much training or the medium to long term, ramping things up too quickly and/or not allowing yourself enough rest and recovery time.
It can impact your sleep, energy levels, digestive function, concentration and sports performance.
The training impact
One of the more obvious ways you can get into an overtrained state is by doing too much training! This might be;
ramping up training too fast
changing more than one aspect of traiing at a time, eg increasing long distance, adding a new weekly run and starting speed work all at the same time
taking up a new additional sport
changing your life so you are doing more walking
a new job that's more active than your last one
It's worth planning out your specific training sessions and runs around everything else that you do that's physically active day to day and making sure you have a training plan that fits you and ramps things up sensibly.
The recovery and rest impact
Many people really underestimate the benefits to and importance of rest days and recovery/download weeks. These are key to allowing your body to adapt to and recover from training; skip these and your body will breakdown, instead of getting fitter and this will lead to overtraining and a slow down or reversal in training progress.
Make sure you have at least one full rest day a week and a recovery/download week every 3-4 weeks where training distance, frequency and intensity drops back noticably.
The life impact
Life factors can profoundly impact training capacity and therefore overtraining risk?
If work is busy and stressful, if you aren't sleeping well, if you are moving home, if someone you know or care for is ill... All of these sorts of things impact your energy and stress/anxiety levels. That background level of stress means your body isn't in the right state to recover properly from your runs and you'll be building up a backlog of fatigue.
Some of these life factors can't be controlled, but what you can do to help is take some time each day to do nothing; be physically inactive and doing something that's mentally calming. Also prioritise your sleep. Those two will help give your body and brain time to recover.
