What causes a “second wind” during a workout – and how to get it


If you’ve ever wondered where that burst of energy comes from – this is what the experts say, from scientists to personal trainers.

Is there anything better than that sudden burst of energy when you’ve been slogging through a workout? One minute, all you can think about is how sore you are and what’s for breakfast, then suddenly – you feel like a new woman. Whether it’s your coffee kicking in or a gift from the workout gods, most of us think of this “second wind” as a blessing.

But have you ever wondered where this sudden burst of energy comes from? Researchers aren’t entirely sure either – however, there are some theories out there, according to the British Journal of Sports Medicine Blog. One possibility is that your body switches from burning carbohydrates to fat.

Another is that it could be something to do with the lactic acid and oxygen in your muscles. Lactic acid requires less oxygen to power your muscles than other sources of fuel, studies show. This means after have a build up of lactic acid during a workout, you may be able to go harder and feel less pain, sports medicine doctor and fitness expert Gabe Mirkin explained in a blog post. “You tell everyone that you suddenly got your ‘second wind,’” he writes. “But actually you started to use huge amounts of lactic acid which requires less oxygen for energy, and your blood became less acidic so you were able to run faster again.”

However, other experts believe the burst of energy we experience is more likely to be in our minds and caused by psychology or neurochemicals, similar to a “runner’s high”, the BMJ notes. According to Mayo Clinic, a runner’s high is caused by a release of endorphins or your “brain’s feel-good neurotransmitters” triggered by physical movement, which effectively suppresses your perception of effort and pain.

However, Joey Foley, a former footballer and co-founder of Punch Pedal House, a spin class gym in New York, told Refinery29 that much of it is to do with the environment you’re in, which is why group exercises classes are so beneficial. “You have thing energy aspect of being next to someone [which] pushes you a little bit more, and gives you energy to take it to the next level”. Other factors could be the lighting, the music, an inspiring instructor or even what you ate beforehand.

As is often the case when it comes to fitness, everyone is different. So the best thing to do? Figure out what gives you that rush and run with it – literally.