Retention of physiology knowledge among medical students in basic science: a cross-sectional study

Abstract

Background

Medical educationists are concerned that the retention of basic science concepts weakens beyond the early years of medical programs, with clinicians rarely using basic sciences in clinical practice. This study was conducted to evaluate the knowledge retention of physiology courses in medical students at Kerman University of Medical Sciences.

Methods

This is a cross-sectional study at Kerman University of Medical Sciences. A retention test was conducted in physiology courses using multiple-choice questions. This study included 104 medical students who had completed their basic science courses. The students were in physiopathology, internship, and clerkship were selected. The mean and standard deviation were applied to analyze the data, and a two-sample t-test, one-way ANOVA, was performed with a significance level of P-value < 0.05.

Results

The results of this study in retention test scores showed that lost knowledge was revealed throughout the years. Additionally, the results showed that in three subjects—gastrointestinal, nervous system, and respiratory—the scores of students in Y1 were higher than those of students in other years. In the course of endocrinology, the highest mean score belonged to the students who entered medical school in Y4, and the difference in mean scores among the different groups was statistically significant (P < 0.001). The mean scores in the urinary system course achieved by the medical students are presented, with students who entered medical school in Y3 having the highest mean scores compared to those in other years.

Conclusions

The key takeaway is that knowledge retention is not passive; it requires active reinforcement through educational strategies. By prioritizing active learning, integrating clinical relevance, and leveraging strategies like retrieval practice and spaced learning, medical educators can enhance long-term retention and better prepare students for clinical practice.

Introduction

Educating in basic science plays an essential role in solving complex medical problems [1, 2], and enhancing the accuracy of diagnostic formulation [3]. Furthermore, basic science knowledge forms the basis of clinical reasoning and helps students develop the practical thinking skills necessary for successful decision-making as a doctor [4]. According to studies, about 50–60% of any unrehearsed knowledge is lost after 2 years and decreases further over time [5]. Despite all the strategies applied to promote more efficient learning, some information learned is forgotten. The “forgetting curve” proposed by Ebbinghaus hypothesises the decline of memory retention over time [6]. According to this curve, learners forget more than 50% of their newly learned material 20 min after the learning process if no repetition occurs; after nine hours, it reduces to 40%, and in 31 days, to 24% [7]. Medical educators are concerned that the retention of basic science concepts diminishes beyond the early years of medical programs, as clinicians rarely apply basic sciences in clinical practice [1, 8].

A significant part of preclinical medical education focuses on quickly acquiring and consolidating a vast amount of knowledge related to physiology [9]. The evidence suggests that physiology is highly applicable to clinical practice (relative to other basic sciences learned in medical school) and that there is frequent physiology-based questioning during the early clinical training period. In another study of medical students by D’Eon, knowledge attrition was demonstrated for physiology, although it was significantly less than the rate of attrition for other topics, such as neuroanatomy [10, 11].

Knowledge acquisition and retention by students are significant in both traditional (teacher-centered) and modern educational systems (student-centered), which primarily focus on problem-based learning [12], because knowledge acquisition and remembering are the starting point for learning [13]. Several factors contribute to the variability in knowledge retention among medical students, including individual factors, educational factors, environmental and social factors, and psychological and emotional factors. This highlights the importance of integrating basic science concepts into clinical contexts early and consistently [14–17]. Zaeemzadeh et al. (2016) noted significant gaps between initial exam performance and retention test results, particularly in pharmacology [18]. According to Mard et al. (2024), the percentage of students who reported having a little or fair amount of physiology content in their memory was significantly higher than that of those who claimed to possess much or very much physiology knowledge in their memory [19]. AlMohanna et al. (2018) reported that only 26% of the 204 medical interns scored ≥ 60% on a physiology knowledge test [14]. Alosaimi et al. (2022) reported a mean score of 3.9 ± 1.8, with nearly 82% of participants scoring less than six marks, indicating an overall poor recall of knowledge in microbiology among interns [20].

Malau-Aduli et al. (2019) examined both basic science knowledge retention and its perceived relevance to clinical practice among medical students, interns, postgraduate speciality trainees, and experienced clinicians. They compared data from 2014 (pilot study) and 2016 (main study). Overall, the mean performance score in the Basic Science Retention Examination was significantly higher in 2014 than in 2016. While no difference was observed in the performances of the two studies in anatomy, the performance of the 2014 cohort was significantly better in biochemistry, pathology, pharmacology, and physiology, the 2016 study achieved higher average scores in social sciences [21].

Knowledge loss in medical education is a multifaceted problem that requires a comprehensive and evidence-based approach to address. Despite extensive research on basic science retention, critical gaps remain. First, longitudinal tracking of physiology knowledge decay within the same student cohort is lacking. Second, the factors driving inconsistent retention rates across studies (e.g., curriculum design, student engagement) are underexplored. Third, while interns’ knowledge loss is documented, little is known about retention trends during medical school itself. Finally, region-specific data, particularly from Iranian medical schools, is scarce. The findings regarding the retention of basic science knowledge can serve as a foundation for implementing more effective educational strategies that consider the learning characteristics of medical students. Additionally, these results can help optimise and tailor the basic science curriculum to meet students’ needs and clinical requirements. In this study, we utilised the retention rate to assess medical students’ long-term basic science knowledge in physiology courses at Kerman University of Medical Sciences and to explore the associations between this knowledge and years of study.

Methods

The current research was a cross-sectional study conducted on medical students at Kerman University of Medical Sciences in 2024. Sampling was performed using a stratified classification method. For sampling, students in the physiology course were classified into three categories based on their average grades in class: good (27% of the highest grades), average (46% of the middle), and poor (27% of the lower grades). The sample size for each educational phase was determined based on the number of students, and participants were selected using a simple random method.

Study context

Medical school at Kerman University of Medical Sciences offers a 7-year medical program that integrates basic and clinical sciences. The first 2.5 years focus primarily on basic sciences, consisting of five semesters covering anatomy, physiology, embryology, genetics, and other foundational subjects. This is followed by two semesters dedicated to physiopathology, which includes pharmacology, pathology, and theoretical courses across all branches of internal medicine. Years 4 and 5 encompass clinical training or externship through five semesters, involving observation and indirect exposure to patients in clinical environments. Year 6 consists of an internship over three semesters, providing direct patient exposure in clinical settings. Upon passing a comprehensive exam in basic sciences, students transition to the clinical stage, where they engage in diagnosing, caring for, and treating diseases. After completing medical school, graduates can enter residency programs to specialise in a specific field of medicine. Until a few years ago, basic science courses were typically taught as independent, discipline-based courses. In this traditional method, students do not receive a comprehensive view of the structure and function of the human body and the relationships between them [22]. At Kerman University of Medical Sciences (KMUS), we changed our general medical curriculum in September 2011. Our traditional discipline-based courses in anatomy, physiology, histology, and embryology were redesigned into introductory basic sciences and eight organ-based systems through horizontal integration.

Participant recruitment

Finally, 104 medical students who had completed their basic science courses and were currently studying physiopathology, clerkship, and internship were invited to participate in this study. The students were in their 2nd semester or higher. They were invited by telephone through the executive expert of the education department. If the students were willing, the necessary information for participating in the exam, including the date and time, was provided in the next call. Students in all four groups were not informed of the exam date, so they answered the exam questions on the same day without prior preparation and based solely on their retentins of courses from previous semesters.

Study tool design

During the meeting of the research team with the head of the physiology department and other colleagues, the research objectives were explained, and they were asked to suggest retention test questions according to the lesson plan in multiple-choice format, similar to the final assessment questions from the semester in which the student passed the course. Multiple-choice questions were designed based on criteria for creating standard multiple-choice questions (Millman criteria) [23]. It should be noted that the number of questions developed was based on teaching hours and was similar to the students’ classroom exam questions for these courses.

A self-administered questionnaire containing demographic data and 69 validated MCQS covering most systems in physiology was used for each course, including the gastrointestinal, endocrine, cardiovascular, respiratory, urinary, and nervous systems. The validity of the questions has been confirmed through the expert panel method, and the test-retest method was also utilised for the reliability of the test. The Cronbach’s alpha coefficient was 0.89, and the internal correlation coefficient of the questions (Alpha-Richardson 0.594) was also obtained.

Student knowledge assessment

The retention test evaluated students’ knowledge. None of the students were informed of the time of the exam to avoid bias, so they took the test without any information about the exam’s timing. The retention exam was held in one day. All the students who participated in the retention test expressed satisfaction with the project, and their scores on the exam remained confidential. While responding to the questions, the participants were not allowed to open a book, consult any other knowledge source, or communicate with colleagues.

Calculating the retention test scores

To examine the retention level in the physiology course, the difference between the scores obtained in the retention test and the final exam scores was calculated. A positive or zero difference indicates no loss of knowledge or even an increase in the individual’s knowledge (if the difference between the scores is positive). Conversely, a negative difference signifies a loss of knowledge; the greater the negativity, the more significant the individual’s knowledge loss in that particular course.

Data analysis

The statistical approach involved analysing the data using a two-sample t-test and a one-way ANOVA test, considering a p-value of less than 0.05 to be statistically significant. The findings are presented as mean values along with their standard deviations (SD). The MCQ data were saved in an Excel file after marking, and statistical analysis was performed using SPSS version 27.0 (IBM, Armonk, NY, USA).

Result

In this study, 104 individuals participated, comprising 46 males (44.2%) and 58 females (56.8%). The average age was 22.78 ± 2.81 years, and the mean academic term was 5.52 ± 2.64 terms (Table 1).

Table 1.

Participants in physiology courses exam

Participant year in medical school	Female % (N)	Male % (N)	Total % (N)
Y4	58% (11)	42% (8)	18.26% (19)
Y3	48.6% (10)	52.2% (11)	20.19% (21)
Y2	55.55% (15)	44.44% (12)	25.96% (27)
Y1	59.45% (22)	40.55% (15)	35.57% (37)
total	56.8% (58)	44.2% (46)	100% (104)

The results of this study showed that the difference between final exam scores and retention test scores was negative in all courses, indicating that students had lost knowledge in physiology courses. Only in the endocrinology course did Y4 students report a positive memorization test score (+ 3.25%). The highest knowledge loss among all four groups occurred in the gastroenterology course, with Y3 students exhibiting greater forgetfulness than the other groups)-70%). Additionally, the scores obtained by students in the respiratory system course indicate that the scores from Y1 and Y2 are higher than those from Y4 and Y3; Y1 has achieved the highest possible scores (Fig. 1).

Fig. 1.

Knowledge loss the percentage of students from different years in the retention exam

The retention test scores

The results of the present study showed that in three courses respiratory, nervous system, and gastrointestinal, the students’ scores in the Y1 were higher than in other years. Additionally, Y2 students’ retention scores in the cardiology course were higher than those for other courses. However, this observation might be partially applicable to another course urinary, which had the highest score in the Y3. In the course of endocrinology, the highest mean score belonged to the students who entered medical school in Y4, and the difference in the mean scores for different groups was statistically significant (P < 0.001). Moreover, in the retention test the result indicates that there was no statistically significant difference between the scores in gastrointestinal physiology across different years. In the course of endocrin physiology, the highest mean score belonged to the students who entered medical school in Y4, and the difference in the mean scores for different groups was statistically significant (P < 0.001). The mean score was, 9.76 ± 4.86 (P < 0.001) for Y2, and 11.08 ± 4.43 (P < 0.001) for Y3. The findings also showed that no significant difference was observed in the cardiology, urinary and respiratory courses based on the entrance year (P < 0.05).

Furthermore, the mean scores in the nervous system course earned by medical students are represented, with the students who entered medical school in Y1 achieving the highest mean score compared to other years (Fig. 1).

The final exam scores

The final exam scores of medical students in different courses are demonstrated. The highest mean score for class grades in the gastrointestinal physiology course belonged to the Y3 and Y2 entrance years, with no significant difference between the years (P > 0.5). Furthermore, in students of Y4 and Y3, the modified system was applied, and no difference was observed between the modified system and the traditional one (p > 0.5). The mean final exam grades for the gastrointestinal physiology course among medical students was 11.43 ± 2.4.

The final exam grades of the medical students in the endocrine system course have been reported. The mean grades for students entering medical school in Y2 and Y1 were 11.5 ± 2.5 and 10.9 ± 2.5, respectively, both of which are higher than the mean for Y4. A similar pattern was observed for Y3, Y2, and Y1.

The final exam grades of the medical students in the cardiovascular system course are categorised by different entrance years. The highest grade was recorded for the Y4 entrance year, which significantly differs from the other groups (P < 0.001).

The final exam grades for the respiratory system course indicate that the mean grades are higher for students who entered medical school in Y3 and Y2; however, the difference between the mean grades in the respiratory course based on different entrance years was not significant (P = 0.89). The final exam grades for the urinary system course reveal that the mean was highest for Y2 (13.9 ± 2.1), which was significantly different from the means for Y4 and other years (P < 0.01, P < 0.001, respectively).

The final exam grades for medical students in the nervous system course indicate that the mean grades for students in Y3 and Y4 are higher than those in Y1 and Y2; however, this difference was not significant (P = 0.8).

The scores from the nervous system course were analysed, revealing no statistically significant difference between the years Y4, Y3, and Y2 (13.5 ± 3, 14.13 ± 1.3, and 14.6 ± 2.4). Notably, the score obtained in Y4 was the lowest, particularly in comparison to Y3 (13.5 ± 3 vs. 14.13 ± 1.3) (Fig. 2).

Fig. 2.

Comparison of students’ retention and final exam scores in physiology courses

Discussion

The results of this study indicated that in three subjects—the gastrointestinal, endocrine, cardiovascular, respiratory, urinary, and nervous systems—the scores of students in Y1 were higher than those in other years, suggesting the effect of time on forgetting. However, this issue relates to another subject, the urinary system, which had the highest score in Y1. In contrast, neurology recorded the highest score in Y3, likely due to changes in the educational system. Though students in this course may have received higher grades in the other subjects, except for physiology, for which the memory test results remain unpublished, the same trend has been observed in the neurology course. Various studies confirm that medical knowledge, particularly fundamental science knowledge, significantly degrades over time after initial instruction [1, 18, 24, 25].

Knowledge loss in medical education is a well-documented yet persistent challenge that undermines the long-term effectiveness of medical training. Multiple studies have highlighted that the degradation of basic science knowledge over time is a ubiquitous issue, with significant implications for both medical students and the healthcare systems they will eventually serve. Our findings regarding medical students’ loss of physiology knowledge align with those reported by others. Specific disciplines, such as biomolecules, genetics, anatomy, microbiology, and pathology, seem to be disproportionately affected [17, 20, 21, 26]. This raises concerns about the foundational knowledge necessary for clinical practice, as gaps in these areas could compromise diagnostic accuracy and patient care [16, 19, 27, 28]. The disproportionate loss in specific subjects suggests that current educational strategies may not adequately address the unique challenges of retaining complex or abstract concepts. Physiology knowledge significantly affects clinical reasoning by providing a fundamental understanding that underpins clinical problems and aids in accurate diagnosis and treatment. Researchers explain how basic science knowledge, through extensive clinical experience, integrates into higher-level clinical concepts or “illness scripts,” facilitating efficient case processing. Teaching basic sciences within a clinical context and introducing patient problems early in the curriculum is essential for developing ‘encapsulated knowledge,’ highlighting the importance of integrating and retaining basic science knowledge [29–31].

Knowledge perceived as clinically relevant is retained more effectively, especially in later years. This suggests that aligning basic science instruction with clinical scenarios could improve retention. Although demographic factors such as gender and student background may influence retention, the evidence remains inconsistent [32, 33]. For instance, Malau-Aduli et al. (2013) found that male and domestic students performed better in specific disciplines [21], While Zaeemzadeh et al. (2023) reported greater knowledge loss among male students [18]. These inconsistencies underscore the need for further research to understand the role of demographics in knowledge retention.

Rote memorization, often facilitated by the widespread availability of question banks, has been shown to hinder long-term retention [34]. This reliance on memorization rather than conceptual understanding creates fragmented knowledge that is easily forgotten. Furthermore, repeated exposure to the material through review and reinforcement enhances retention [35]. However, the challenge is to design educational strategies that encourage meaningful engagement with the material rather than superficial repetition.

To address knowledge loss, medical education must shift from passive learning and rote memorisation to active, clinically integrated, and conceptually driven approaches. Several evidence-based strategies show promise, and repeated testing on previous material has been shown to improve long-term retention [14, 35, 36]. Incorporating retrieval practice into the curriculum can help counteract the “forgetting curve” and reinforce key concepts. Revisiting material at spaced intervals enhances retention [1, 7, 35]. This approach aligns with principles of cognitive science and can be integrated into medical curricula through structured review sessions or longitudinal assessments. Additionally, connecting basic science knowledge to clinical practice enhances retention by making the material more meaningful and applicable [21, 37–39]. Case-based learning and clinical simulations serve as effective tools for achieving this integration. Furthermore, shifting focus from memorization to conceptual understanding through project-based learning enhances comprehension and retention [34, 40]. This approach encourages students to engage deeply with the material and apply it in practical contexts. Structured revision tests, along with review sessions, have been shown to enhance retention [41, 42]. This strategy may be especially effective for high-stakes subjects such as physiology, anatomy, and pharmacology.

The flipped classroom approach in medical physiology enhances both short- and long-term academic performance, promotes essential lifelong learning skills, and is positively received by students, all without detracting from their performance in other concurrent courses [43, 44].

The findings from the studies reviewed have several important implications for medical education. Passive learning and rote memorization are insufficient for long-term retention. Educational strategies must prioritise active recall, spaced repetition, and clinically relevant contexts to ensure that knowledge is retained and applied effectively. Students tend to focus on what they know will be assessed. Therefore, assessment methods should encourage a deep understanding of concepts rather than the memorization of isolated facts. This could involve incorporating more open-ended questions, case studies, and practical assessments into exams. The widespread availability of disclosed test questions and answers can lead to superficial learning. To mitigate this issue, educators should consider developing dynamic assessment tools that test conceptual understanding rather than the recall of specific questions. Longitudinal studies tracking knowledge retention throughout the entire medical curriculum are needed to better understand the dynamics of knowledge loss and the effectiveness of interventions. Such research could provide valuable insights into how to optimize medical education for long-term retention.

The study has two notable limitations. Its cross-sectional design prevents establishing causality between loss of knowledge and influencing factors such as curriculum design, teaching methods, academic semesters, or gender. Moreover, factors like prior education, study habits, or external stressors (e.g., mental health issues) may affect knowledge retention but are difficult to control in a cross-sectional design. Students may inaccurately recall or report their knowledge levels, particularly if the study relies on self-reported data. This can lead to overestimating or underestimating knowledge loss. Additionally, this study was conducted at a single center and within one academic course, so a broader understanding of the subject requires more courses and additional centers.

Conclusion

This study highlights significant knowledge loss over time, particularly in basic science subjects. The key takeaway is that knowledge retention is not passive; it requires active reinforcement through educational strategies. By prioritizing active learning, integrating clinical relevance, and leveraging strategies like retrieval practice and spaced learning, medical educators can enhance long-term retention and better prepare students for clinical practice. However, addressing this issue also requires a critical examination of current assessment practices and a commitment to ongoing research to refine and improve educational strategies. Ultimately, the goal is to ensure that medical students not only acquire knowledge but retain and apply it effectively throughout their careers, thereby improving patient outcomes and advancing the field of medicine.

Author contributions

All authors have conceived and designed the concept and road map of the study. S.Sh, M.Kh, MR. D. contributed to the data collection, searching the literature, and writing the initial draft of the manuscript. M.O, MR. D. and S.Sh critically reviewed the manuscript for its content, originality, methodology, statistical, usage of the English language and accuracy of interpreted data. All authors have made substantive contributions and attest to approving the final manuscript.

Funding

The Kerman University of Medical Sciences (KMUS).

Data availability

No datasets were generated or analysed during the current study.

Code availability

All software applications used are indicated in the manuscript.

Declarations

Ethics approval and consent to participate

All study protocols have been conducted under the approval of the Kerman university of medical sciences. All methods were carried out in accordance with relevant guidelines and regulations. The participation was completely voluntary and informed consent was obtained from all participants.

Consent for publication

Not applicable.

Conflict of interest

The authors declare that no competing and financial interests exist.

Ethical approval

This study is the result of a research plan approved with ethical code number (IR.KMU.REC.1394.399) of the Kerman University of Medical Sciences.