Summer Training and Sleep: What the Research Says About Performance and Injury

Last updated: October 2026

More sleep has been linked to better athletic performance: when 11 collegiate basketball players extended their sleep by about 111 minutes a night, sprint times and shooting accuracy improved (Mah et al., 2011). A systematic review of 25 studies found napping and sleep extension may improve physical and cognitive performance, although high-quality evidence is limited (Cunha et al., 2023). Below is what those studies tested, what the research says about sleep and injury, and what pillow height changes for anyone training hard this summer.

Key takeaways

When 11 collegiate basketball players added about 111 minutes of sleep a night, sprint time fell from 16.2 to 15.5 seconds (Mah et al., 2011).
In adult athletes, a review of 12 prospective studies found only limited evidence linking poor sleep to injury (Dobrosielski et al., 2021).
A Pillowise fitting takes three measurements (shoulder width, neck circumference and neck length) and adds sleeping position and bed type to choose from seven sizes.

Can more sleep improve athletic performance?

In a study at Stanford, 11 men's varsity basketball players kept their usual sleep for 2 to 4 weeks, then aimed for at least 10 hours in bed each night for 5 to 7 weeks (Mah et al., 2011).

Nightly sleep rose by about 111 minutes. Sprint time improved from 16.2 to 15.5 seconds, free-throw accuracy rose 9 percent, and three-point accuracy rose 9.2 percent. Reaction time and daytime sleepiness improved as well.

The study had no control group, and practice over the season may account for part of the change.

What do the sleep studies in athletes show overall?

A systematic review pooled 25 studies of sleep interventions in athletes published between 2011 and 2021 (Cunha et al., 2023).

Napping and sleep extension were studied most often, and both may improve physical and cognitive performance. Removing electronic devices at night and cold water immersion showed no effect. The authors noted a limited amount of high-quality evidence.

Does poor sleep raise injury risk?

For adult athletes, the evidence is thinner than often claimed. A systematic review of 12 prospective cohort studies found limited evidence of an association between poor sleep and injury in adult athletic populations (Dobrosielski et al., 2021).

The authors concluded that current evidence does not support poor sleep as an independent risk factor for injury in adults. Sleep is worth prioritizing for performance and recovery, and the injury question remains open.

Why does sleep matter for soreness and pain?

In a crossover experiment, 14 healthy adults spent one night without sleep. Afterward they were more sensitive to heat, cold, blunt pressure and pinprick pain (Schuh-Hofer et al., 2013).

That does not mean one short night causes an injury. It does mean a hard training day can feel harder after poor sleep.

What does pillow height change overnight?

Performance and the neck are separate questions, and the pillow belongs to the second one. In a radiographic study of 16 adults, raising the pillow from 0 to 10 to 20 cm increased T1 slope and C2-7 Cobb angle while neck tilt decreased (Kim et al., 2015).

In a pilot EMG study of 15 adults lying on their side, the height matched to shoulder width produced the lowest neck and shoulder muscle activity (Jiao et al., 2025).

Why do generic pillows miss?

A standard contoured pillow, not fitted to the individual, performed no better than ordinary shapes in a randomized study of 106 side sleepers (Gordon et al., 2009). No single optimal pillow height can be specified, because it depends on four variables that differ from person to person: cervical alignment, body dimension, contact pressure, and muscle activity (Lei et al., 2021).

What we measure

Pillowise is a fitted cervical pillow that licensed healthcare providers measure and dispense, made in seven sizes.

Our sleep specialists take three measurements: shoulder width, neck circumference, and neck length. Combined with sleeping position and bed type, an algorithm identifies the best-fitting pillow from seven sizes.

Shoulder width is the measurement the EMG study found mattered most. A height matched to it produced the lowest neck and shoulder muscle activity during side sleeping (Jiao et al., 2025), and body dimension is what drives the individual optimum (Tian et al., 2025).

A systematic review of 11 studies covering 309 participants identified a 7 to 11 cm unloaded central height among the parameters supporting spinal alignment and sleep comfort (Radwan et al., 2021). The size is chosen from those three measurements plus sleeping position and bed type, rather than from a single stock height.

Pillowise pillows are made from premium Dutch memory foam and certified to OEKO-TEX Standard 100, meaning every component has been tested against the standard's limits for harmful substances.

Scope

The athlete studies measured sleep, performance, and injury, not pillows, and the largest performance study had 11 participants and no control group. No study has tested whether a pillow changes athletic performance or injury risk, and we make no such claim. The pillow studies are small, and the most recent systematic review found no clear advantage for any pillow type in chronic neck pain (Ghosh et al., 2025).

For providers

Summer brings patients who are training more, playing more, and sleeping less. Asking about sleep hours alongside training load gives the recovery conversation something concrete.

Sleep position and bed type are the inputs that matter for pillow height, whether the patient is an athlete or not.

A fitted pillow extends the work of the visit into the hours between visits, alongside the exercise, manual therapy, and other care the provider is already delivering.

Common questions

Does sleeping longer help athletes perform better?

In some studies, yes. Basketball players who added about 111 minutes of sleep a night ran faster and shot more accurately (Mah et al., 2011), and a review of 25 studies found sleep extension and napping may improve performance (Cunha et al., 2023). The evidence base is small.

Does poor sleep cause sports injuries?

Not on current evidence in adults. A review of 12 prospective studies found only limited evidence of a link, and the authors concluded it does not support poor sleep as an independent risk factor (Dobrosielski et al., 2021).

Can a pillow improve athletic performance?

No study has tested that, and we make no such claim. What pillow height changes is neck alignment and neck muscle activity during sleep (Kim et al., 2015; Jiao et al., 2025).

Is a contoured pillow from a store enough?

Not reliably. A standard contoured pillow, not fitted to the individual, performed no better than ordinary shapes in a randomized study of 106 side sleepers (Gordon et al., 2009), and no single optimal height can be specified because it depends on four variables that differ from person to person (Lei et al., 2021). A contour helps only if its height matches the person using it. That is what the fitting settles, in a provider's office.

Find a Pillowise provider or become one

Pillowise pillows are clinically measured and dispensed exclusively through licensed healthcare providers as part of broader sleep, posture, and recovery education.

To locate a Pillowise provider near you, visit: Find a Reseller

Licensed healthcare providers interested in offering Pillowise may register here: Become a Reseller

References

Cunha, L. A., Costa, J. A., Marques, E. A., Brito, J., Lastella, M., & Figueiredo, P. (2023). The impact of sleep interventions on athletic performance: A systematic review. Sports Medicine - Open, 9(1), 58. https://doi.org/10.1186/s40798-023-00599-z

Dobrosielski, D. A., Sweeney, L., & Lisman, P. J. (2021). The association between poor sleep and the incidence of sport and physical training-related injuries in adult athletic populations: A systematic review. Sports Medicine, 51(4), 777-793. https://doi.org/10.1007/s40279-020-01416-3

Ghosh, S. K., Goyal, M., & Goyal, K. S. (2025). Effect of pillow on pain, disability and sleep quality in patients with chronic neck pain: A systematic review. Rehabilitación, 59(3), 100922. https://doi.org/10.1016/j.rh.2025.100922

Gordon, S. J., Grimmer-Somers, K., & Trott, P. (2009). Pillow use: The behaviour of cervical pain, sleep quality and pillow comfort in side sleepers. Manual Therapy, 14(6), 671-678. https://doi.org/10.1016/j.math.2009.02.006

Jiao, R., Xiao, W., Wang, M., Yu, S., & Li, H. (2025). The impact of pillow height on neck muscle activity: A pilot study. Sleep and Breathing, 29(1), 40. https://doi.org/10.1007/s11325-024-03219-6

Kim, H. C., Jun, H. S., Kim, J. H., Ahn, J. H., Chang, I. B., Song, J. H., & Oh, J. K. (2015). The effect of different pillow heights on the parameters of cervicothoracic spine segments. Korean Journal of Spine, 12(3), 135-138. https://doi.org/10.14245/kjs.2015.12.3.135

Lei, J.-X., Yang, P.-F., Yang, A.-L., Gong, Y.-F., Shang, P., & Yuan, X.-C. (2021). Ergonomic consideration in pillow height determinants and evaluation. Healthcare, 9(10), 1333. https://doi.org/10.3390/healthcare9101333

Mah, C. D., Mah, K. E., Kezirian, E. J., & Dement, W. C. (2011). The effects of sleep extension on the athletic performance of collegiate basketball players. Sleep, 34(7), 943-950. https://doi.org/10.5665/sleep.1132

Radwan, A., Ashton, N., Gates, T., Kilmer, A., & VanFleet, M. (2021). Effect of different pillow designs on promoting sleep comfort, quality, & spinal alignment: A systematic review. European Journal of Integrative Medicine, 42, 101269. https://doi.org/10.1016/j.eujim.2020.101269

Schuh-Hofer, S., Wodarski, R., Pfau, D. B., Caspani, O., Magerl, W., Kennedy, J. D., & Treede, R. D. (2013). One night of total sleep deprivation promotes a state of generalized hyperalgesia: A surrogate pain model to study the relationship of insomnia and pain. Pain, 154 (9), 1613-1621. https://doi.org/10.1016/j.pain.2013.04.046

Tian, S., Yao, C., Wang, Y., Cao, X., Sun, Y., Wang, L., & Fan, Y. (2025). The individualized optimal pillow height and neck support design for side sleepers. Medical and Biological Engineering and Computing, 63 (2), 535-544. https://doi.org/10.1007/s11517-024-03204-x