By Darran Clemmit
It’s the New Year and everyone is keen to get back into shape, and for some people that means going to the gym and training in the morning before work. While it’s obvious we have to fit training into our days wherever convenient, training first thing in a morning has some added risks and these should be considered when looking at training programmes and activities.
When we lay down on a night to sleep the pressure on the spine is reduced, this reduces the applied hydrostatic load to a level below the osmotic pressure in the intervertebral discs, allowing an inflow of fluid and the transfer of nutrients into the discs. This inflow of fluid and nutrients results in an increased spine length and greater pressure in the disc.
This is why you are tallest in the morning or if you lay in bed for a long time (around nine hours or more) the fluid transfer is so great that it results in ‘swollen’ discs, which can result in back ache upon rising. Over the course of the day applied pressure to the discs forces this fluid out, resulting in a reduction in spine length and intervertebral pressure.
So what does this mean?
Well, after rising in a morning (or any time of day where you have laid down for a significant amount of time asleep) the greater disc pressure means that the annulus (the fibrous outer ring of the disc) is subject to much higher stresses under bending, and the end plates fail at a much lower compressive load. In short, exercising in a morning carries a much greater risk of injury, both from long term wear and structural failure caused by overload.
So, getting out of bed and starting your day with some sit-ups is one of the worst things you can do for your back with the high compression and shear forces under a flexed spine. Of course, I’m not saying this will always cause injury; some people can tolerate many extremes, but it certainly increases the risk.
Given the above, it would be wise to take precaution against something we know to give a large increase in risk of back injury and wear. Ideally a programme would be designed so that training took place later in the day when some disc fluid has been forced out and the spine has a better capacity for loading and bending. This isn’t always possible due to time constraints or personal preference, so an alternative must be considered.
Around 90% of the fluid loss over the course of the day happens within about an hour of rising. Therefore, if morning training is unavoidable, the individual should ideally have been up and moving around for at least an hour, warm up should be longer and loading increased more gradually than for someone training later in the day. It’s probably also worth designing training programmes so that exercises which involve the more risky movements, repetitive bending or twisting, loads approaching one rep maxes and any high impact work are avoided in sessions shortly after rising.
Train hard, and stay healthy!