I'm wondering if it does any harm to take two centrum pills after doing heavy exercise. Ever since I developed asthma living in Gibraltar, the doctor recommended I take them but when I exercise heavily, I usually take another right after my workout.

Heavy exercise for me can be 4-5 hours on a road bike burning between 2000 and 2500 calories...sometimes more depending on the route, heat, etc....

I was told this could be extremely bad for me taking two pills but is that necessarily true? My standard daily burn rate is 2400 calories per day so I have quite a high metabolism rate. I figured the average adult male burns 2000 per day so if I'm knocking off 4400+ in one day, surely I'd require more than average vitamins?

Perhaps I've got this wrong but I've not felt bad taking the double dosage and I would only do so after exercise.

Can anyone let me know if this would be an issue?

True, I do eat more but not excessively and I try to keep my mealtimes very regular. I also do these workouts about once a week along with 10-12km of running every 3-4 days but I burn between 800-1000 in those.

Also interesting you mention 2400. I read the average adult male burns 2k per day but a little Googling and I found an active man of my weight should be in the region of 3100 per day!

A 165-lb (77kg), high-activity man needs to consume 3,100 calories whereas a low activity man of the same weight is just 2400 calories.

http://www.livestrong.com/article/263430-how-many-...

Interesting stuff, when you consider on an active exercise day, you'll be spending over 5000. Here's me thinking I eat too much... apparently not....

Excess b vitamins can give you a bit if acne. Don't overdo vitamins it's a waste of money, if you eat regularly and reasonably healthy a multivitamin a week Is the most I'd ever take.

If you are a veggie or a student living of pasta and rice there a good idea. Even then I wouldn't worry too much.