Caffeinated coffee boosts strength and sprint performance in trained men, regardless of chronotype

A new study published in Chronobiology International has found that caffeinated coffee improves physical performance in trained male athletes, regardless of whether they are morning or evening types. The research showed that caffeine enhanced grip strength, back strength, and sprint performance at both morning and evening testing times. However, caffeine had no significant effect on cognitive performance or perceived exertion.

The study was conducted by a team of researchers in Türkiye to explore how caffeine affects physical and mental performance in athletes who differ in their natural circadian rhythms, or chronotypes. Chronotype refers to whether someone performs better in the morning or evening, and it is thought to be shaped by internal biological clocks that influence sleep, alertness, and energy levels.

Athletic performance is known to vary throughout the day due to factors such as body temperature, hormone levels, and sleep patterns. Some research suggests that evening types perform better in physical tests later in the day, while morning types may excel earlier. However, findings in this area have been inconsistent. Moreover, while caffeine is widely used by athletes to enhance performance, less is known about how it interacts with chronotype or time of day. The researchers aimed to address these gaps by evaluating how moderate doses of caffeine in coffee form affect trained individuals with distinct chronotypes when tested in both the morning and evening.

The study included 17 trained male athletes between the ages of 18 and 25 who regularly engaged in strength training. Eight participants were identified as morning types and nine as evening types using the Morningness-Eveningness Questionnaire. Participants reported moderate daily caffeine consumption and were screened to ensure they had no sensitivity to caffeine or underlying medical conditions that might interfere with the study.

The research design was double-blind, randomized, and crossover. Each participant completed four test sessions in total: caffeinated coffee in the morning, caffeinated coffee in the evening, decaffeinated coffee in the morning, and decaffeinated coffee in the evening. The caffeine dose was standardized to 3 milligrams per kilogram of body weight, delivered through Nescafé Gold, and consumed 60 minutes before testing. Physical and cognitive tests were conducted between 8:00 and 10:00 in the morning and between 16:00 and 18:00 in the evening, with a 48-hour washout period between sessions.

The testing battery included handgrip and back strength tests, a lower-body Wingate sprint test measuring both peak and average power, a cognitive flanker task to assess reaction time, and the Borg Rating of Perceived Exertion scale to gauge how hard the participants felt they were working.

The researchers found that caffeinated coffee significantly improved handgrip strength, back strength, and performance in the Wingate sprint test. These improvements were evident regardless of chronotype or time of day, although some nuanced differences emerged. For example, morning types performed significantly better after consuming caffeinated coffee in the morning compared to the evening. Similarly, evening types showed better grip strength in the evening following caffeine intake than they did in the morning.

In terms of peak power output on the sprint test, both chronotype groups experienced marked improvements with caffeine. Morning types in particular showed strong gains whether tested in the morning or evening. For average power output, morning types again showed enhanced performance with caffeine, with the greatest improvements occurring during evening testing.

Interestingly, caffeine did not significantly affect cognitive performance. Participants’ reaction times in the flanker task did not differ between caffeinated and decaffeinated conditions. The researchers suggested that the relatively low caffeine dose, individual differences in caffeine metabolism, and the limited scope of the cognitive task may have contributed to this outcome. They also found no statistically meaningful differences in perceived exertion between caffeine and placebo sessions, even though physical performance improved.

The researchers acknowledged several limitations. While the study controlled for many variables, including sleep and caffeine abstinence before tests, some measures relied on self-report, which may introduce bias. The study also focused only on men, limiting its generalizability. In addition, the relatively small sample size may have made it difficult to detect more subtle effects, especially for cognitive outcomes. Another limitation is that only one type of cognitive test was used, which may not capture the full range of possible effects on mental performance.

Despite these limitations, the study offers new insights into how caffeine interacts with time of day and chronotype to influence athletic performance. It suggests that caffeine can be a useful supplement for enhancing strength and sprint performance across the day, even for athletes with different circadian preferences. However, it may not enhance short-term cognitive tasks like reaction time in this context.

The researchers suggest that future studies could investigate how genetic differences in caffeine metabolism influence performance, and whether similar results are found in female athletes. More detailed cognitive assessments could help determine whether caffeine affects other aspects of mental functioning during physical exertion. They also recommend exploring how other forms of caffeine delivery—such as capsules, energy drinks, or chewing gum—might produce different effects, given differences in absorption rates.

The findings could have practical applications for athletes, coaches, and sports nutritionists. Tailoring caffeine intake to an athlete’s chronotype and training schedule could potentially maximize performance while minimizing side effects. For instance, morning types may benefit more from caffeine during early workouts, while evening types might see greater returns during later sessions. This personalized approach could be especially useful for optimizing training and competition strategies in sports where strength and power output are critical.

The study, “Effects of caffeinated coffee on physical and cognitive performance: Chronotype and time of day study,” was authored by Yakup Köse, Raci Karayigit, and Muhammed Uygar Sertkaya.