Interview With Olle Lagerquist - Neuroscience and Exercise Physiology Researcher Interviewed by Luke Allison - July 2009
CRITICAL BENCH: Olle please give us your background:
I began weightlifting while earning my BS in Exercise Physiology at Simon Fraser University. I competed in Olympic style weightlifting between 1999 and 2002 at the provincial and national level. In 2002 I began my masters in Exercise Physiology but switched into the field of Neuroscience. I recently completed my PhD in Neuroscience at the University of Alberta. My main area of research has been how electrical stimulation affects human muscle; however the area of circadian rhythms has always been an interest that I have maintained.
CRITICAL BENCH: What was your hypothesis going into this study?
Intuitively we hypothesized that morning people and evening people would show patterns of strength that were exactly the opposite. For example, morning people would demonstrate the greatest strength in the morning and the evening people would demonstrate the greatest strength in the evening. However this did not turn out to be the case.
CRITICAL BENCH: Where there any problems you encountered with research design or other limitations?
We limited our strength measures to plantar-flexion because this muscle group lends itself to rather easy examination of central nervous system function. This is partly due to the ease at which we can electrically activate this muscle group (the main nerve - tibial, runs right behind the knee and is easy to access). I would find it interesting to attempt this experiment again with other more complex movements.
CRITICAL BENCH: What assessment process did you use to determine if people were better acclimated to mornings or nights?
We used a questionnaire developed by Horne and Osteberg in 1976. This is the most widely used tool for evaluating a person's preference for being a morning or evening person.
CRITICAL BENCH: How can our readers tell which group they might be in?
The questionnaire we used can be found in the following journal article.
Horne JA and Osteberg O. A self-assessment questionnaire to determine morningness-eveningness in human circadian rhythms. International Journal of Chronobiology 1976; 4(2):97-110.
CRITICAL BENCH: Was it difficult to find the two groups of nine? Did you gain any insight into the distribution of extreme morning or night people across some population?
The two groups of nine were not too difficult to find, although I think this was a stroke of luck. In a typical population we expect there to be about 50% "neither" types, people who are classified as "afternoon" types. However, I would say that currently the true distribution of morning, afternoon and evening people is not particularly well established. It would certainly be useful to have a survey of several thousand people to establish this.
Estimates thus far suggest that 50% of the population is afternoon types and 25% morning and 25% evening types.
CRITICAL BENCH: What behaviors characterize extreme morning and night people?
Extreme morning people are typically characterized by the following traits:
Waking up early without the need for an alarm
Waking up at the same time every morning regardless of when you go to bed
Feeling energetic and alert first thing in the morning
Having a preference for doing physical and mental tasks in the morning
Begins to feel tired and slows down in energy level as the day goes on, especially after dinner.
Extreme evening people are typically characterized by the following traits:
Need an alarm to wake up in the morning
Will sleep late if they go to bed late
Feels very sluggish in the morning and takes a long time to properly wake up
Has a preference for physical and mental tasks later in the evening
Begins to feel at their peak later in the evening, typically after dinner
CRITICAL BENCH: Was there a noticeable difference in performance between the two groups?
Yes. Morning people were very stable in their performance with no big changes throughout the day. Evening people grew stronger as the day progressed reaching their peak by 9:00 pm.
CRITICAL BENCH: It seems that the night group experiences maximal central nervous system drive around 9:00pm. What is maximal central nervous system drive?
Maximal central nervous system drive in this case refers to the ability of the central nervous system to maximally activate muscle tissue. When the central nervous system is "more excitable" it will be easier to generate more force with the same amount of voluntary effort. Thus when we have maximal excitability within the central nervous system we maximize the ability to generate muscular forces with the same amount of voluntary effort.
Think of "excitability" as analogous to the gain knob on an amplifier. The amplifier increases the signal when the gain is turned up even though the input (maximal voluntary effort in this case) stays the same.
CRITICAL BENCH: There seems to be a certain inherent importance associated with the phenomena of "spikes" whether it comes from periodization, supplementation, or sensitivity manipulation. Does a spike in central nervous system drive appear more beneficial than a more constant drive profile?
That is an interesting question. If people that have large "spikes" in central nervous system excitability can identify when these occur I think it could be useful to train at those specific times to maximize athletic performance and gains. Our results would suggest that morning people do not have these spikes while evening people do. However it remains to be determined if this is a benefit for evening people compared to morning people.
CRITICAL BENCH: Are there any clear implications for athletes either in terms of organizing training or preparing for competition?
Our results would suggest that evening people are at a greater disadvantage if the competition occurs in the morning than a morning person who is competing in the evening. If an evening person knows in advance that they will have to compete in the morning it is likely beneficial for them to train in the morning for a period of time leading up to the competition; however I don't know of any research that has evaluated this specifically or how long this adaptation might take.
CRITICAL BENCH: How will this study impact your future research?
Some interesting questions have arisen from this research. For instance:
What are the effects of caffeine and other drugs that affect the central nervous system on morning vs evening people throughout the day?
How quickly can we convert a morning person to an evening person and vice versa?
We expect this relationship to also affect other muscle groups and more complex movements, but this should be tested.