Host: Can a woman in her second trimester do more strenuous exercise? Dr. John Schmitt: Well again, as we just talked about if they are used to doing strenuous exercise, yes, assuming it doesn't hurt or really cause them discomfort. I think as you get into the second trimester a great rule of thumb is that you don't want to increase your core body temperature so if you are going to do prolonged or rather strenuous exercise you want to do it inside or in a place where it's relatively cool where your body temperature won't go up. You don't want to get real dehydrated exercising. So for prolong periods of exercise you would have to drink lots of fluids as well as stay cool and finally, you don't want to get in an exercise regimen that puts you into your anaerobic zone or where you are utilizing oxygen very inefficiently and you are building that lactic acid and things like that and for most people that means if you take your pulse your pulse so to stay somewhere below about a 140-150 beats per minute to stay within your aerobic zone or if you don't take your pulse, if you are out of breath to the point you can't speak in multiple word sentences you are probably getting into your anaerobic zone and you need to back off. So I think my patients that exercise a lot like long distance runners realize that themselves very quickly that they do not have the same endurance and they will mediate their activity, they compensate for that and they don't get in their anaerobic zone and they don't go too far and they don't get dehydrated. So be in cool, stand hydrated and don't sustain your heart rate to half or more than just a few minutes.