I was wondering the same thing myself the other day...
My docs won't let me run, or do impactive stuff, but I just added the pool as well. I have always been a weights gym rat junkie pre my bike days. I think for ME, I've concluded this, fwiw...
On the days I expect my body to perform at it's best with lifting, I do not ask it to perform hard cardiovascularly. I'll do just a spin class at a light resistance working low aerobic intensity, then go hammer out my weights. I'm good and warmed up, but not overworked.
Maybe you could try speed walking on the treadmill with some brief jogs/sprints instead of the full run on weight lifting days? Or, you also could try a split routine. When you run harder, only work parts of your upper body vs your legs.
Even though swimming is not impactive like running, it's very hard work! I suck at swimming btw. I'm working at changing that statement. With my asthma and trying to breath right with the stroke, it's just mentally exhausting besides other respects.
If I plan to swim AND lift in the same day... I will alternate backstroke laps with kickboarding with fins (head out of water). I wear my Polar HRM, so I know I'm still working it--just lower intensity. I think it can be deceiving if you are not used to the pool because you don't see the sweat pouring off your body like a ride or run. About a half mile... but I'll do it after my full weight routine... if the lifing is my priority activity for the day.
Meat, meat, meat... I LOVE meat lol. Hard boiled eggs. Tons of nuts. I try to get a lot of low fat dairy in. I still feel like I crave protein. Still figuring it out. But, those things help on fueling me.
Lastly... this one is a BIGGIE as a woman. Your period...
I don't feel so bad when I'm actually having my period, but it's when I'm ovulating. When my uterous is preparing for a would be baby and sucking all the extra red blood cells to it... I find I feel anemic. Just SO tired, sick, totally messed up... (btw, I'm 40, and my perimenopause starting kickin about mid thirties)
Also, for me during that time is when I'm carrying water weight and post egg drop start to shed it. I swear I become a "human-non-stop-pee-ing-machine"!!!No matter how much I drink, I feel "flu-ish" and dehydrated. I can hardly pedal it out, lift, anything.
During the ovulating time, I do all my activities in recovery mode. Low aerobic zone/shorter distance. Weights maybe just two sets vs three and 8 reps in a set vs 10. Or something... in a word: *modify*.
Hope this helps.
Miranda



... 
No matter how much I drink, I feel "flu-ish" and dehydrated. I can hardly pedal it out, lift, anything.
.
Reply With Quote
Going to try the different protein powder soon barring anymore blizzards that is. All I have to say is Texas is sounding better and better every day. 