If you have been unlucky enough to have contracted COVID-19 you should have ceased all your training to enable your body to fight the virus and get you back healthy as soon as possible.
The virus can be debilitating and can mean you have to put off training for possibly several weeks. It can also leave you with residual fatigue meaning you feel tired after only a short, low intensity bought of activity.
If you monitor your resting heart rate and/or your heart rate variability, these will help you decide when you are well enough to resume training. When you return to training it is important that you start with short, easy sessions and if you encounter any symptoms of the virus, your resting heart rate increases or your heart rate variability decreases cease training and take a further period of rest.
You should aim to slowly and gradually build up the volume of your training before you start to introduce any higher intensity work. Take things steady and listen to your body to ensure you return to full fitness safely.