Monday, November 15, 2010

Caffeine Blunts Exercise Induced Hypotensive Response and Increases Post Exercise Blood Pressure

I told you about the positive effect of caffeine supplementation on the post high intensity interval training fatty acid oxidation, only yesterday. Today, I have to tell you that all that could be a bad idea, if you are prone to hypertension, because, as scientists from Brazil found (Cazé. 2010), the same caffeine that may make you shed some additional grams of fat, will block the hypothensive, i.e. blood pressure lowering effect of exercise and may drive an already high blood pressure into the danger zone:
Seven hypertensive subjects (52.3 +/-3.3 years), being 5 women, accomplished two walk sessions with 40 minutes of duration, in two days of training, having previously ingested CA (4 mg/kg of body weight) or placebo (PL). BP and heart rate were verified previously to the ingestion, after 15, 30, 45, 60 minutes of the ingestion, at rest and with 10, 20 and 30 minutes after exercise. [...] BP mean increased from 124.9/80.9 mmHg before ingestion to 129.4/84.3 mmHg 60 minutes later (p< 0.05). In the recovery period, after 30 minutes of exercise, hypotensive answer was observed in the PL procedure (decrease of 122.6/79.4 mmHg to 115.7/78.6 mmHg), while in the procedure with CA, BP was significantly higher than at rest (increase of 124.9/80.9 mmHg to 136.9/90.9 mmHg, p<0.05).
If you already have blood pressure issues and are exercising in order to get rid of these, it would thus be wise to refrain from caffeine consumption before or in the course of your exercise sessions.