Basically any stimulant is going to have some effect on your body taken before a workout. I've observed it just by simply monitoring heart rate during identical cardio workouts with and without caffeine. My heart rate is nearly 10bpm higher with a stimulant than without. If I were pushing myself to the limits such as in HIIT, that could concern me as I have reached tachycardia during HIIT before. If it is a lower intensity fat burning workout I wouldn't be so concerned. Just be careful-I always recommend using heart rate to monitor cardio workouts, especially HIIT!
The following is from:
www.everybody.co.nz/research/hrt_ephedra.htm
Ephedra and caffeine add strain to athletes' hearts
People who consume ephedra and caffeine before they exercise alter their cardiovascular system, placing greater demands on their heart, says a South Dakota State University study. The combination of ephedra and caffeine increases the hypersensitive response before, during and after exercise, and increases systolic blood pressure before exercise. That higher rate pressure results in more work for the heart. The findings were presented at the Experimental Biology meeting in San Diego, April 11-15. The study included five men and five women who were given either 150 milligrams of caffeine and 20 milligrams of ephedra or a placebo. They were then monitored while at rest, during exercise and after exercise. The people who took the caffeine/ephedra had higher hypertensive response after 60 minutes of rest. That response remained higher at 30 and 60 minutes of exercise. The people who took the caffeine/ephedra also had higher systolic blood pressure while they were resting and had higher mean arterial pressure. Ephedra is a controversial herb marketed as an energy booster and weight loss aid. It's been linked to almost 100 deaths, including high school, college and professional athletes who have collapsed during games or practice. (Health Scout)
03-06-05, 11:29 PM
