Why You Hurt After Exercise

We all know the dreaded muscle soreness and aches and pains after exercise. Waking up the next morning and walking like John Wayne. Why does this happen though? Why can’t you just wake up the next morning and bounce around like a spring chicken? Delayed onset muscle soreness (DOMS) is a curse that every gym fanatic has to endure. It turns out though, that in the short run your body doesn’t like exercise and it takes time for your body to realise that what actually happening is a good thing!

Whilst this could be a bit of a rabbit hole to go down, we will summarise this with the two main factors: muscle damage and metabolic accumulation. Muscle damage is one of the reasons why our muscles hypertrophy (grow) during resistance training and metabolic accumulation is how we get better at cardiovascular exercise.

When you train with resistance, microscopic tears happen in the muscle fibres. Once the muscle fibre has experienced damage there is a cascade of inflammatory hormones in response. At this moment, the body is interpreting training and exercising as a threat which it must heal from (hence why you plateau if you do the same thing all the time) and the inflammation response is part of starting the healing process (or the adaption process in this context). Your muscles will be “stiffer” than usual and generally be a bit warmer due to the hormones circulating around.

When you train, your body has the choice of 3 energy systems to choose from the aerobic system, the anaerobic system and the phosphocreatine system. If you are resistance training, it is likely you will be mainly using the anaerobic energy system. This pathway burns glucose in the absence of oxygen and creates lactic acid as a by-product. The lactic acid can’t be recycled into the energy system so causes the pH level of the muscle to decrease (muscle acidosis), this is when you “feel the burn”. Lactate often stays in the muscle body for up to 72-hours but this can be reduced with light cardiovascular exercise to help pump blood around the body and remove waste products.

Whilst this is scary and can often put you off exercise, the first session is always the worst. When you start a new programme, change exercise, volume or intensity the first session is likely always to be the worst as your body is experiencing a new stimulus. As your body becomes accustomed to the exercises it’s doing, the level of DOMS you experience should be reduced. It is important to remember your body is reacting and adapting to a threatening stimulus and will always look to protect itself and adapt to overcome the threatening stimulus. So even though it might hurt now, making sure you keep up a good routine and let your body become better.

So the next time you hurt after having your PT session here at Sandown, just remember this and thank our wonderful PT team. If you’re interested in starting on your personal training journey then click the link HERE: https://sandownsports.co.uk/personal-training/contact-fitness-team/