I signed up to a gym for a few months. I did an 60 minutes of intense exercise 2-3 times a week. The only problem being that on my days off my hubby works so I have no child care so I was going after work. I saw improvements in my physical stamina and muscle tone in about 4 sessions. The problem I had was that as soon as I began to see an improvement I got run down with viruses. I would manage about 10-14 days then get ill, have a week off to recover, get back into it for a couple of weeks then ill again and so on and so on.
When I felt well I felt really good physically. I found it too tiring to go after work and so I have stopped going and cancelled my membership. It's a shame I think I could really tone up and improve my stamina over time but I got fed up of getting run down.
Also being over tired made me more grumpy.
As for effect on w/d perhaps the continuous viruses were a sign of my body being unable to tolerate the exercise or maybe it was just me picking up the germs through being in such a public place using machines that have been in contact with goodness knows how many people. Think of all those people going to the gym to 'sweat out' there colds! YUCK!
