Sleep is an essential physiological process that regulates brain function, learning, and memory consolidation, all of which are critical for academic success in students [1]. The quality and quantity of sleep influence neurocognitive performance, attention span, and problem-solving abilities [2]. Insufficient sleep has been linked to impaired academic achievement, mood disturbances, and decreased overall well-being [3].

Medical students are considered a high-risk group for sleep disturbances due to their demanding curriculum, long study hours, and irregular schedules [4]. Studies have shown that a large proportion of medical students report sleeping less than the recommended 7–9 hours per night, with academic pressure, electronic device usage, and stress being major contributing factors [5, 6]. Sleep deprivation in this population has been associated with reduced concentration, slower cognitive processing, and lower examination performance [7].

While the negative impact of short sleep duration is well documented, emerging evidence suggests that excessive sleep may also impair cognitive efficiency, possibly due to circadian rhythm disruption and underlying health issues [8, 9]. The relationship between sleep duration and academic performance has been studied in various student populations; however, findings remain inconsistent, with some studies reporting a linear association and others indicating an optimal “mid-range” sleep duration for peak academic performance [10, 11].

In the context of medical education, where academic performance directly influences future clinical competence, understanding the role of sleep is crucial. Despite the growing awareness of sleep hygiene, there is a paucity of data from developing countries, particularly in South Asia, examining the quantitative association between sleep duration and academic outcomes in medical students [12].

The present study was conducted to assess the association between average nightly sleep duration and academic performance among undergraduate medical students. By identifying the optimal sleep range for enhanced academic achievement, this research aims to inform student wellness programs and promote healthier study–sleep patterns.

Study design and setting:

This was a cross-sectional analytical study conducted at a tertiary care medical college in India.

Study population and sampling:

The study included undergraduate medical students from all academic years (first to final year). A total of 312 participants were selected using stratified random sampling to ensure proportional representation from each year of study.

Inclusion criteria:

• Enrolled full-time in the MBBS program
• Aged between 18 and 25 years
• Provided informed consent to participate

Exclusion criteria:

• History of diagnosed sleep disorders (e.g., insomnia, sleep apnea)
• Ongoing psychiatric illness or use of sedative medications
• Chronic medical conditions likely to affect sleep patterns or cognitive performance

Data collection tool:

A structured, self-administered questionnaire was used to gather data on sociodemographic variables, self-reported average nightly sleep duration in the past month, and the most recent internal examination scores (expressed as a percentage). Sleep duration was classified into three categories:

1. Short sleep – <6 hours/night
2. Adequate sleep – 6–8 hours/night
3. Long sleep – >8 hours/night

The questionnaire was pretested on 20 students (not included in the final analysis) to ensure clarity and reliability.

Outcome measures:

The primary outcome was academic performance, measured by the percentage score obtained in the latest internal assessment.

Statistical analysis:

Data were entered into Microsoft Excel and analyzed using SPSS version 26. Descriptive statistics were presented as mean ± standard deviation (SD) for continuous variables and frequencies with percentages for categorical variables. Differences in mean academic scores across sleep-duration categories were compared using one-way analysis of variance (ANOVA). Pearson’s correlation coefficient was calculated to assess the relationship between average sleep duration and academic scores. A p-value of less than 0.05 was considered statistically significant.

A total of 312 undergraduate medical students participated in the study, with a mean age of 21.4 ± 1.9 years. The majority were female (58.7%), and representation from all academic years was proportionate.

Sleep Duration Distribution and Academic Scores

The largest proportion of students (46.8%) reported an average sleep duration of 6–8 hours per night, followed by those sleeping less than 6 hours (38.1%) and more than 8 hours (15.1%). Mean academic scores varied significantly across these categories, with the highest performance observed in the adequate sleep group (Table 1).

Table 1. Distribution of participants by sleep duration and mean academic scores

One-way ANOVA showed a statistically significant difference in academic scores across the three groups (F=19.42, p<0.001). Post-hoc analysis revealed that the adequate sleep group scored significantly higher than both the short-sleep and long-sleep groups (p<0.001 for both comparisons).

Correlation Between Sleep Duration and Academic Performance

Pearson’s correlation indicated a moderate positive association between average nightly sleep duration and academic performance up to 8 hours (r=0.42, p<0.001). Beyond 8 hours, scores plateaued and slightly declined.

Table 2. Correlation between sleep duration and academic scores

These findings suggest that optimal academic performance was associated with an average sleep duration of 6–8 hours, while both shorter and longer sleep durations were linked to lower scores (Table 2).

This study examined the association between average nightly sleep duration and academic performance among undergraduate medical students. The results demonstrated that students obtaining 6–8 hours of sleep had significantly higher academic scores compared to those with shorter or longer sleep durations. A moderate positive correlation between sleep duration and performance was observed up to the optimal threshold of 8 hours, beyond which academic scores plateaued.

The positive association between adequate sleep and academic achievement observed in this study aligns with previous research highlighting sleep’s role in cognitive functions such as attention, memory consolidation, and problem-solving [1–3]. Medical students, due to rigorous academic demands, often experience reduced sleep duration, which has been linked to diminished cognitive efficiency and poorer learning outcomes [4,5].

Our findings that short sleep (<6 hours) correlates with lower academic performance are consistent with studies reporting that chronic sleep restriction impairs neurobehavioral functioning and exam scores [6,7]. Sleep deprivation has been shown to reduce prefrontal cortex activity, affecting executive functions critical for academic success [8]. Similarly, insufficient sleep has been linked to decreased alertness, reduced working memory capacity, and slower information processing [9].

Interestingly, our results also indicated that excessive sleep (>8 hours) was associated with a decline in academic scores. This trend has been reported in prior work, suggesting that oversleeping may disrupt circadian rhythms and be associated with underlying health or lifestyle factors detrimental to cognitive performance [10,11]. Some studies have proposed a U-shaped relationship between sleep duration and academic outcomes, where both extremes are disadvantageous [12,13].

The optimal range of 6–8 hours identified here supports recommendations from the National Sleep Foundation and World Health Organization for young adults [14]. Promoting adequate sleep through targeted interventions, such as time management training and sleep hygiene education, may help medical students enhance their academic outcomes [15].

Strengths and limitations

The strengths of this study include its stratified sampling method ensuring proportional representation across academic years and the use of objective examination scores rather than self-reported grades. However, its cross-sectional design limits causal inference, and self-reported sleep duration may be subject to recall bias. Additionally, factors such as sleep quality, mental health, and study habits, which may influence academic performance, were not assessed.

Medical students who achieved 6–8 hours of nightly sleep demonstrated significantly better academic performance compared to those with shorter or longer sleep durations. Promoting healthy sleep habits within medical curricula may help optimize cognitive function and academic success.

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