The rocker - real name IAN KILMINSTER - was hospitalised after suffering from dehydration and exhaustion at the concert in Germany in July.
But he dismisses the incident as an "occupational hazard" and insists he's fitter than ever.
Lemmy says, "It was about 150 degrees on stage and our music takes a lot of energy. I got through the show all right, but then 'Boom!' I was gone.
"It's always a shock when your body refuses to carry on for a while but it's an occupational hazard."