Understanding Allostatic Load: Feb ‘23
Hey! It’s Tom and Emma at High North Performance,
We hope all’s well and that your training is going smoothly, as most of us are busy laying down a foundation for the year and season ahead!
Let’s get into this month’s edition of In-Form:
Musing
This month we wanted to talk about a concept known as the ‘allostatic load’ and how this needs to be considered when planning your training.
Allostatic load refers to the cumulative physiological ‘wear and tear’ that results from the body's efforts to adapt to chronic stressors over time. These stressors encompass all of our daily activities, and can include physical (e.g. both training and non-training activity), psychological (e.g. work or financial stress), and environmental (e.g. altitude, and temperature) factors.
If the stress response is activated too frequently or for too long, it can lead to a state of chronic stress and result in long-term negative effects on health and well-being.
Chronic life stressors also directly impact the ability to train and to adapt effectively to training. Studies have shown, for example, that inadequate sleep can slow down recovery, and increase the risk of illness and injury (for paper review, see here). Conversely, we can see the power of sleep in a recent study that suggests that even a 20-minute nap may help enhance antioxidant defences after exercise, potentially helping to promote recovery.
We often work with time-crunched athletes who already have a high allostatic load from work, family commitments, and often limited sleep. With these athletes, it’s very important to make sure the overall training load is appropriate. It’s not simply a case of filling all available time with training, as this can lead to overtraining, maladaptation and illness!
Another common scenario is when athletes travel to extreme environments (e.g. altitude or heat). In these cases, there’s a sudden upward shift in environmental stress, and training needs to be reduced accordingly, until the athlete has adapted to the change in environment.
Some tips for monitoring your allostatic load include:
Being mindful of any acute changes e.g. change in environment, job, moving house etc., and proactively reducing your training load until you’re feeling more settled.
Taking a daily measure of heart rate variability and/or resting heart rate - deviations from the norm (whether higher or lower) for more than a day or so can be a sign of increased stress.
Being aware of sleep. Lack of sleep can contribute to a higher allostatic load, but can also be a key indicator that your allostatic load is high if you’re struggling to get to sleep or to stay asleep.
If you suspect your allostatic load may have increased for any reason, then it’s often wise to reduce your training accordingly. The key exception to this would be if your allostatic load has increased as a result of a planned and purposeful increase in training load (such as to build a fitness peak ahead of a key race).
Science
In this month’s paper review, we take a look at a novel interval design that aims to improve the amount of time spent riding close to VO2max or maximal aerobic capacity.
High-intensity decreasing interval training (HIDIT) increases time above 90% VO2peak
This study compared three different interval sessions to look at the time to exhaustion and the time spent above 90% VO2max among 12 amateur level cyclists.
The three interval designs were:
Long intervals: 3-mins ‘hard’, and 2-mins ‘easy’ until the point of exhaustion.
Short intervals: 30-sec ‘hard’ and 20-sec ‘easy’ until the point of exhaustion.
Progressively decreasing intervals: interval length starting at 3-mins, and then decreasing to 2-min, 1-min, 45-sec, and finally 30-sec. Once 30-sec intervals were reached, these were repeated until the point of exhaustion. Like the long and short intervals, a 3:2 work:recovery interval was used, so for example, after the 3-min hard interval, there was a 2-min easy recovery period, after the 2-min interval, there was a 1-min 20-sec recovery, and so on.
In all sessions, the 'hard' intervals were performed at each athlete’s 5-min max power. The ‘easy’ intervals were performed at roughly a Zone 3 intensity (83% of each athlete’s critical power on average)
Our detailed paper review is here. These are our key take-homes:
The progressively decreasing intervals allowed notably more time to be spent riding close to VO2max before the point of exhaustion (roughly 5-mins vs 3-mins for the other two designs).
The total time spent close to VO2max was quite low for all designs, so in practice, we’d probably recommend doing two blocks of efforts, separated by 5-mins of easy riding, but stopping each block before the point of exhaustion.
There was considerable variability in the athletes’ responses to the different interval sessions, and some did favour one of the other two designs. This highlights the importance of including some variety in your training and that individualisation of training prescription is vital.
News
First up, we have a new article looking at the discrepancy between indoor and outdoor FTP. If you want to learn more about this, and see why TrainerRoad have dropped the ball a bit, we’d love for you to read it here.
Next, we’re pleased to report that we’ve added to our training plan library, and now have more volume options for our VO2max, threshold power, ultra-distance and ‘anaerobic booster’ plans. If you’re interested, you can check them out here.
Finally, we hope you’ll all join is in wishing our coached athlete Zoe Langham, as well as other riders from the Wahoo Le Col team (whom we are partnered with) all the very best for the UCI Cycling eSports World Championships tomorrow! You can watch the action on Zwift’s YouTube channel.
That’s it for this month. As always you can find our Cycling Physiology Guide and Hill Climb Handbook on our website too. For those that are already customers, we thank you greatly for your support and feedback!
All the best,
Tom and Emma
