Glycogen Replenishment

A strategy referred to as “sleep low-train low” involves scheduling carbohydrate intake around the training schedule so that some, but not all, workouts are performed in a state where the muscles do not have maximum glucose available to do the work.  Several randomized trials with trained male athletes have investigated the effects of this strategy on skeletal muscle (Bennett et al., 2021).  Lane et al. (2015) devised the strategy with the idea that keeping glycogen levels low for a long time after an intense workout (all night and then throughout a lower-intensity workout the next day) would have a beneficial effect in training the muscles for endurance.  They called the strategy “train-high, sleep-low”.  Marquet et al., (2016) included a bedtime protein drink, and found that their participants were able to increase their time on a 10 km race by over a minute on average after three weeks following the training schedule.  Interestingly, Waterworth et al. (2020) found that athletes given a placebo carbohydrate drink after the evening workout had intermediate performance on a high-intensity test following the morning workout, compared to those given the actual carbohydrate drink or a drink that was disclosed to be non-carbohydrate.  The authors conclude that the mere perception of carbohydrate availability improved performance. 

 

Of note, the participants in the studies I have mentioned were all trained, competitive athletes.  Only the Bennett et al. (2021) study included any females (8 out of 55 participants).  While recreational athletes and women athletes may be interested in trying this strategy, I think it would be important for them to recognize that differences between their physiology and that of the participants should be taken into account.  The mechanisms by which the muscles are fueled for endurance exercise are different for women than for men, and thus it should not be expected that the optimal training strategy for men would also be ideal for women (Oosthuyse et al., 2021).  In addition, women’s bodies may use glycogen differently at different stages of the menstrual cycle (Matsuda et al., 2022).  Another finding is that women don’t increase their muscle glycogen by eating carbs at the same rate that men do (Tarnopolsky et al., 2001).

 

Considering all the known differences in how women’s muscles work compared to men’s, it seems important to conduct studies that include women as participants and that analyze their results separately from the men if we are to recommend a training strategy to women.  It may also be that a strategy such as “sleep low-train low” could be effective for women during a certain phase of the menstrual cycle (Walker et al., 2000), and the training could be scheduled to take advantage of this phenomenon rather than being frustrated by its ineffectiveness when scheduled at the wrong time of month. 

 

References:

 

Bennett, S., Tiollier, E., Brocherie, F., Owens, D. J., Morton, J. P., & Louis, J. (2021). Three weeks of a home-based “sleep low-train low” intervention by improves functional threshold power in trained cyclists: A feasibility study. PLoS ONE, 16(12), 1–20. 

 

Henselmans, M., Bjørnsen, T., Hedderman, R., & Vårvik, F. T. (2022). The Effect of Carbohydrate Intake on Strength and Resistance Training Performance: A Systematic Review. Nutrients, 14(4). 

 

Lane, S. C., Camera, D. M., Lassiter, D. G., Areta, J. L., Bird, S. R., Wee Kian Yeo, Jeacocke, N. A., Krook, A., Zierath, J. R., Burke, L. M., & Hawley, J. A. (2015). Effects of sleeping with reduced carbohydrate availability on acute training responses. Journal of Applied Physiology, 119(6), 643–655. 

 

Marquet, L.-A., Brissewalter, J., Louis, J., Tiollier, E., Burke, L. M., Hawley, J. A., & Hausswirth, C. (2016). Enhanced Endurance Performance by Periodization of Carbohydrate Intake: “’Sleep Low”’ Strategy. Medicine & Science in Sports & Exercise, 48(4), 663–672. 

 

Matsuda, T., Takahashi, H., Nakamura, M., Kanno, M., Ogata, H., Ishikawa, A., Yamada, M., Kamemoto, K., & Sakamaki-Sunaga, M. (2022). Influence of menstrual cycle on muscle glycogen utilization during high-intensity intermittent exercise until exhaustion in healthy women. Applied Physiology, Nutrition & Metabolism, 47(6), 671–680. 

 

Oosthuyse, T., Florence, G. E., Correia, A., Smyth, C., & Bosch, A. N. (2021). Carbohydrate-Restricted Exercise With Protein Increases Self-Selected Training Intensity in Female Cyclists but Not Male Runners and Cyclists. Journal of Strength & Conditioning Research, 35(6), 1547–1558. 

 

Tarnopolsky, M. A., Zawada, C., Richmond, L. B., Carter, S., Shearer, J., Graham, T., & Phillips, S. M. (2001). Gender differences in carbohydrate loading are related to energy intake. Journal of Applied Physiology (Bethesda, Md. : 1985), 91(1), 225–230. 

 

Walker, J. L., Heigenhauser, G. J., Hultman, E., & Spriet, L. L. (2000). Dietary carbohydrate, muscle glycogen content, and endurance performance in well-trained women. / Alimentation en hydrate de carbone, reserve de glycogene musculaire et performance d’endurance chez des femmes entrainees. Journal of Applied Physiology, 88(6), 2151–2158. 

 

Waterworth, S. P., Spencer, C. C., Porter, A. L., & Morton, J. P. (2020). Perception of Carbohydrate Availability Augments High-Intensity Intermittent Exercise Capacity Under Sleep-Low, Train-Low Conditions. International Journal of Sport Nutrition & Exercise Metabolism, 30(2), 105–111.