TAKEN FOR A RIDE

By the end of a brutal sportive, your body has been through a lot. But what exactly goes on under the bonnet? James Witts charts what happens inside you and finds out how to get through the toughest rides a little more comfortably

- James Witts

Anyone who's really pushed their limits on a bike during an event will have experienced burning thighs, screaming lungs, a pounding heart and oceans of sweat. But have you ever wondered what is actually happening to your body when you pedal? And how you can energise it to make you arrive at the finish line in the most efficient way? We lift the lid on the physiology and psychology involved so you can leave the competition wheezing in your wake.

HEART OF THE MATTER

You're lined up in your sportive pen. The nerves are cranked up, meaning your kidneys' adrenal medulla is stimulated into action and so secreting adrenaline. It's the hormonal cause of that 'flight or flight' mechanism and results in a cascade of cardio repercussions before you've even set off. "These include an increase in heart rate and cardiac output," says cardiologist Andre La Gerche. "It also leads to a rise in blood pressure and metabolism." Further adrenaline-fuelled physiological changes include the relaxation of the smooth muscle in the wall of the bronchioles, which leads to a better supply of air to the alveoli; an increase in respiration rate; and dilation of coronary blood vessels and those of skeletal muscle, thus providing increased blood supply to those areas.

So, your body's started to prepare for the physical challenge ahead. But it's still a shock to the system when you pedal, especially if your ride opens with a high mountain pass. This is where 'oxygen uptake kinetics' comes into play. Essentially, this is the speed at which your body can deliver oxygen to working muscles from a state of rest and so swiftly click into a steady state.