People claim that they are a morning or an afternoon person and perceive that they perform better in their daily tasks at the corresponding time of day. The question here is does this also apply to athletic or sporting performance as well? If it does then is there any scientific evidence to support the finding?
Effect on athletic performance:
Well to answer the first question, yes the time of day can impact on your athletic or sporting performance. This is a topic that I stumbled upon while looking into ways to reduced and counter the effects of jet lag and was surprised by what I read and the scale of the impact that the time of day can have on performance.
First up lets address the affect on performance before discussing the scientific reasoning behind the claim. As you will see while the time of day impacts on performance it isn’t quite as simple as having one time of day that is optimal for training or competing, in fact you can almost split the our training session into two parts depending on our goals of your training in order to match the time of day at which we would perform best.
The first point of interest is that we display both greater strength and endurance in the afternoon, coupled with a reduction in the perceived level of exertion for exercise of the same relative intensity. At first glance you could argue that this isn’t the case for everyone and that it purely applied to the sample groups tested, yet if you look more closely and examine the world records for middle distance running, swimming and strength events comparing then with the time that they were broken you will see almost all records were set later in the day, more specifically after 7pm.
On the other hand we display greater mental performance, short term memory and faster reaction times in the morning. While this has little impact if sporting events are often later in the day it can have a significant impact when it comes to training, if the training you have planned has a high technical element for example such as learning the technique for an Olympic lift, learning set routines in a team sport or training your reactions then you will see greater results and a larger return on the time you spend training if you perform your training in the morning.
Science behind the findings:
Having looked at how the time of day can impact your athletic performance lets look at the reason behind it, your body is controlled by circulating hormones the majority of which have daily cycles (circadian rhythms) which impact nearly all physiological function within the body. The main hormone of interest here is Melatonin, this is the hormone that is responsible for sleep, ironically the circadian rhythm of melatonin is also the cause of jet lag.
The levels of circulating melatonin are closely controlled by light and therefore the time of day. The Suprachiasmatic nuclei and Pineal glands in the eye and brain are sensitive to light. During the day when it is bright and there is plenty of light the release of melatonin is detected by the suprachiamsatic nuclei suppressing the release of melatonin from the pineal glands. However as it begins to get darker and the light drops melatonin is gradually released causing the circulating levels to increase.
These daily fluctuations in the levels of Melatonin circulating in the blood have a knock on affect on a number of physiological variables including heart rate, blood pressure, core body temperature and as discussed therefore mental performance, strength and muscular endurance.
To elaborate, as melatonin levels gradually increase throughout the day as light slowly drops heart rate will vary by up to 4 beats.min even if you were to lie perfectly still and avoid any physical exertion all day. Your heart rate will be lowest at roughly 7am just as it is beginning to get light and melatonin levels are high. Your heart rate will peak at roughly 2pm when it is light and melatonin circulating in the blood is at its lowest.
Another example is core body temperature, this is lowest during the night and early morning reaching its lowest point at roughly 6am when melatonin levels are high, as the melatonin levels drop through the day the core body temperature will slowly increase peaking around 6pm. This is just as light starts to drop and melatonin begins to be released.
Now while the variations in physiological factors seems small, combined they can have a significant impact on performance as explained earlier. So are there any practical recommendations that we can take from this, well in an ideal world yes. If we could choose when we train then we could tailor our training to match the time of day we would perform best maximising the returns from the time we put in, for example performing skills training or reaction work in the morning and strength or endurance work in the late afternoon or early evening. Unfortunately when we train is often dictated by other commitments in our lives.
I guess the main point to take away is that if we have what we perceive as a poor session one day compared to another it may not be due to our ability or lack of effort, maybe it is the time of day that we performed each session that has affected the result.