Those who feel faint after a strenuous workout can take heart: that queasy, slightly dizzy sensation isn\u2019t necessarily a sign of being out of shape.<\/p>\n
In fact, a glass or two of one\u2019s favourite drink post-workout may be all that is needed to perk back up.<\/p>\n
This is one of the main conclusions of new research, co-led by Brock University Professor of Kinesiology Toby M\u00fcndel, published earlier this month.<\/p>\n
Conducted by an international research team, the study aimed to better understand the dynamics and treatment of post-exercise hypotension \u2014 a decrease in resting blood pressure that can last up to a few hours following intense exercise.<\/p>\n
While this blood pressure reduction is positive for health overall, M\u00fcndel says the downside is that the sudden drop can cause fainting.<\/p>\n
The Canada Research Chair in Extreme Human Environments says previous studies have been inconclusive as to whether \u201cyour hydration status \u2014 whether you\u2019ve had enough to drink, or not \u2014 makes that worse.\u201d<\/p>\n
Some researchers have attributed post-workout fainting to a reduction in blood volume. This is caused when there is less water in the blood due to dehydration, which has the effect of thickening the blood.<\/p>\n
\u201cThe research is mixed, with some studies saying hydration has an impact on post-exercise hypotension and others saying it does not,\u201d says M\u00fcndel, adding the team was driven to find a clear answer.<\/p>\n
The study saw 12 men first undergo 10 minutes of high-intensity exercise following their regular pre-exercise intake of fluids. After finishing the exercise, they recovered for one hour while their blood pressure was checked.<\/p>\n
The next time the men came in, they were banned from drinking anything in the 12 hours before the workout. Participants reported feeling weaker, dehydrated and had lower blood pressure than when they\u2019d kept up their usual fluid intake.<\/p>\n
Participants again went through 10 minutes of intense exercise after going 12 hours without fluid. Afterward, they chose to consume either 1.2 litres of a sports drink within five minutes or 1.1 litres whenever they wanted to, over the course of an hour.<\/p>\n
Both approaches fixed the problem of weakness, dehydration and low blood pressure after the exercise, says M\u00fcndel.<\/p>\n
\u201cHowever, if you chug water after exercise, there might be other benefits,\u201d he says. \u201cHaving a big volume of liquid afterwards brought your heart rate and body temperature down quickly.\u201d<\/p>\n
M\u00fcndel says the research findings come at a time when many people are fasting as part of religious observances. Some of this fasting includes abstaining from liquids, as well as food, for long periods of time.<\/p>\n
\u201cIf people go a day without drinking or eating anything, and then they go to the gym or play soccer, they might want to have some fluids afterwards to stop them from fainting,\u201d he says.<\/p>\n
The research findings also apply to firefighters and military personnel, who may not always get the hydration and nutrition they need to perform their physically demanding jobs, says M\u00fcndel.<\/p>\n
Although the researchers used a sports drink in the study, water or any other liquids will have the same impacts, he says.<\/p>\n
M\u00fcndel recommends that, ideally, people be well-hydrated before undergoing intensive exercise. Drinking something afterwards, however, can make up for being dehydrated beforehand, he says.<\/p>\n
The study, \u201cThe effect of hypohydration before and different rehydration strategies after severe intensity exercise on post-exercise hypotension in men<\/a>,\u201d was published on March 4 in the European Journal of Applied Physiology<\/em>.\u00a0The 13-member research team was co-led by M\u00fcndel and Tze-Huan Lei, from the Xi\u2019an University of Science and Technology in China.<\/p>\n Supporting the research was funding from the federal government\u2019s Natural Sciences and Engineering Research Council of Canada and the Canada Research Chairs Program.<\/p>\n <\/p>\n <\/p>\n A post shared by Brock University | BrockU (@brockuniversity)<\/a><\/p>\n<\/div>\n<\/blockquote>\n\n