I've been doing regular exercise (running & swimming) for many years now, so I'm used to it, but the last few months I have been getting very fatigued afterwards. My performance is impaired too (slower generally).

If I run or swim in the morning and I have nothing else on later in the day I will usually end up falling asleep. This is strange for me as I have always previously found exercise energising.

I have had bloods run and the only thing that can back was low Vit D, I've been on supplements for 6 weeks now. The other med I'm on is Zoloft (5 weeks) - the fatigue predates going on this, and does seem to have improved a little on this med but not totally.

My BMI is low end of healthy range and has been that way for years, so no change there.

Anyone else experience this? Any thoughts?