When you are in ketosis, you’ll be restricting your carb intake. This will stop your muscles from accessing sugar which your body heavily relies on.
When your muscles don’t have enough fuel (glucose in this case) the ability for them to handle high intensity exercise is limited.
You may engage in activities such as walking, swimming, cycling, etc. As long as you maintain a moderate pace, you’ll not be taxing your body. Weight training is great too. Just don’t overdo it.
Low intensity aerobic exercises are great. So are yoga and Pilates sessions. Stability exercises are good too.
Once you’re fully keto-adapted, you can progress on to higher-intensity training. It’s always during the initial stages when you have to be most careful
As mentioned earlier, Tyson Fury who was prepping for his fight in December 2018 was consuming 5500 calories a day but exercising non-stop. He still lost 140 pounds and became fighting fit.