:( I am skinny, like BMI 19-20 but I can't really do much because CUNDISHUNS. I would like to build more cores strength to help back pain but I can't sweat (like seriously, I could lose vision, can't even do hot showers) any recommendations? I walk to and from all errands and can lift about 20 lbs. I do a lot of volunteer work but it's mostly little stuff like picking up clean towels for events or delivering kits to health fairs. It kinda sucks to not be able to lift anything or run. I ride my bike but I fall off a lot (balance center is wonky, so it's like being drunk when you are sober trying to ride a bike). I think my body fat percentage is around 20%. I literally cannot get fat or it will kill me faster so I control my cal intake pretty stiffly.