Running issue 9/2007 September 2007: Cheat the lazy morning; About physiology in the morning

While considering the differences between morning training and training at other times of the day from the perspective of physiology, we should realize that the physiological processes enabling the proper functioning of the body are so complex that in fact, it is impossible to perform an identical training from the perspective of physiological processes, even if the training is performed at the same time of the day. This results from the fact that each time the body tries to attain relative homeostasis through various physiological mechanisms and each change, e.g. different food, weather, pressure, or mood (representing the state of the neural system) affects the state of physiological processes which accounts for the fact that trainings that are the same from the physiological perspective may actually differ (even though the same methods and techniques of training may be employed). For instance, we are performing an intensive interval training during which without any problems we reach a high heart rate that we can maintain and another time the same training is difficult even though the time of the training is the same. However, the difference lies in other factors e.g. different pressure, temperature, or mood and sometimes a competitor additionally introduces caffeine in order to stimulate the body which should guarantee effective performance in the training. From the perspective of physiology, caffeine stimulates the neural system by enhancing the activity and shortening the reaction time, accelerates the heart rate, increases the ejection volume, furthermore, it increases the permeability of the sarcoplasmatic reticulum for calcium ions causing increased muscle contractility. Through the increased accessibility of cyclical AMP it causes the acceleration of metabolism and increased physical efficiency and also intensification of lypolisis. So, the application of this substance affects the effectiveness of the training because it influences a number of physiological processes accounting for the fact that the same training can have different effectiveness, depending on many factors that affect the state of physiological processes in the body. In other words, from the perspective of physiology, each difference in the conditions in which the training is performed triggers different activity of the physiological processes and so, the effectiveness of the training, and in practice it is difficult to attain identical conditions of training.

When considering the differences between the morning training and the training at the other times of the day, we have to assume that the training is identical and performed in similar conditions which involve: the same diet, work routines, place of the training session as well as similar climatic conditions and the only difference is the time of the training. In such a case physiological differences (concerning training in the morning and at the other times of the day) will still be differentiated according to the following aspects of physiological processes:

1. Biological rhythms,
2. Condition and state of the nervous system excitation,
3. Organism nutrition – condition of metabolic changes.

Biological rhythms – also called daily rhythms are daily fluctuations of the intensity of different physiological processes and hormonal activity. Among the most important daily rhythms influencing the runner’s training we can list:

• Heart rate frequency. The resting frequency differs depending on the time of the day and reaches its highest level between 9 a.m. and 5 p.m. and the lowest one between 1 and 4 p.m. Depending on the time of the training the changes of the heart rate can amount to at least 15 beats a minute during the submaximal effort, especially if the training is performed between 7 a.m. and 6 p.m. The above described broad-spectrum of changes regarding training may on one hand result in performing the morning training in a different heart rate zone if it is monitored only be the speed of running and on the other if the training is monitored by the heart rate it can increase the intensity in order to reach a given zone and at the same time change the quality of metabolic changes (it can result in the increase of lactate and difficulty in performing the whole training, especially if it is performed before 9 a.m.).
• Body temperature – is also subject to daily changes and it is lowest between 3 – 5 a.m. and the highest about 6 p.m. The difference between the lowest and the highest is usually not greater than 10C which seems irrelevant for training but certainly requires longer morning warm-up so as to reach optimal temperature for muscle work during the main part of the training.
• Systolic blood pressure – increases significantly between 8 a.m. and 8 p.m. after which it decreases reaching its lowest value at 2 a.m. The fluctuations in systolic blood pressure at different times of a day are of no major importance to morning or later training sessions. However, they may result in a need to use various stimulants (e.g. coffee) which will influence training by affecting a number of physiological processes.
• Hormonal activity is also subject to daily rhythms. From the perspective of training the most important rhythms are: height hormone (hGH) with its highest concentration at around 6 p.m. and 3 a.m.; cortisol (having strong catabolic activity) with its maximal concentration between 6 a.m. and 4 a.m. and minimal concentration between 8 p.m. and 4 a.m.; testosterone with its highest concentration in the morning hours (around 8 a.m.) and the lowest around 2 a.m.; insulin whose concentration mainly depends on the glucose level in blood. A training based on daily rhythms naturally uses their increased or decreased (cortisol) activity and because of this it is more effective. It is vital to indicate that organism equipped with adaptive abilities adjusts itself to the time of the training also within hormonal activity thus support the natural biological clock and adjust the organism to a specific training time, which however requires consistency and regularity. Changing the training times has detrimental effects as it impedes adaptation on the physiological level.

State of nervous system excitation

This criterion is often neglected in training design as the diagnosis of the condition of the nervous system is very difficult thus rarely applied. This criterion involves parasympathetic and sympathetic nervous system loads. Generally speaking, during sleep parasympathetic system is active and during waking state sympathetic one. It needs to be emphasized that this division is an overgeneralization as these two systems interact which results in difference in their activation during different states of the organism. The increased activity of the sympathetic system during sleep may hinder the realization of the training plan in the morning if it is focused on intensity as there may be difficulties with achieving a given heart rate. In such case morning training should be verified by adjusting it to morning hours and applying less intensity of exercises especially in the first period which is indispensable to organism’s adaptation to morning training. In case of the evening training, type of work which may overload nervous system needs to be taken into consideration. If the work before training was mentally intensive, generated tension and stress the training should be focused on aerobic exercises and analogically in case of monotonous and tedious work the focus of training should be on more intensive exercises. Such course of action prevents overtraining which is overload of one system (parasympathetic or sympathetic) decreasing effectiveness of the training. What is more, the condition of the nervous system reflects the level of coordination skills which even for a runner are very important as they enable high economy of running (intermuscle coordination) which saves energy and increases running speed at a similar intensity of running. Summing up, choosing the daytime for training and designing a training a programme we need to take into consideration condition of the nervous system so as to appropriately choose training methods and techniques.

Nutrition of the organism – state of metabolic changes

In this criterion the most significant difference occurs in the processes determining metabolism, namely in the proportions of anabolic (building) to catabolic (downbreaking). In the morning, after waking up, due to a decrease in glucose concentration the catabolic processes start to intensify (night catabolism) and as a result organism’s proteins are burnt, mostly branched chained amino acids produced in muscles for energetic purposes. Such state results in intensified degradation of muscles which can be further increased by empty stomach training. This kind of training is less effective and consequently the injury risk increases. In practical terms empty stomach training is performed by the athletes who whish to accelerate weight loss as a result of intensified lipolysis, which however does not change the degradation effect in the muscle proteins and higher injury risk. The solution is appropriate anticatabolic food supplementation before training session e.g. BCAA, glutamine, etc. or appropriate meal. In case of morning training, due to the time needed for digestion the appropriate food supplement seems to be more practical. In case of a training session at later hours the problem does not occur since the metabolic optimum (understood as the balance of anabolic to catabolic processes) occurs due to possibility of ingesting meals. To sum up, choosing morning training, pre-training nutrition should be appropriately planned so as not to waste the training effect.

Summary

Recapitulating the difference between morning and later in the day training at the physiological level, I would like to emphasize that these differences need to be viewed mostly by the function of starting the training as this is the only factor which results in different physiological changes. Other factors are relative to each training session performed even at the same time of the day. To sum up, the best time for training is between 8-11 a.m. and 5-8 p.m. as the physiological conditions vital for effective training are the best. What is more, the adaptive abilities of our organism allow for performing training at any time, although we should allow for 3-4 week adaptation period for a different training time.