[How to scientifically estimate sample size in physiological research].

OBJECTIVE To bring about physiological researchers' attention of the importance of sample size estimation. METHODS The significance as well as the current problems of sample size estimation were illustrated and the commonly-used sample size estimation methods were introduced. RESULTS The basic concepts and necessary premises of sample size estimation were stated. The estimation processes and results under two different circumstances were elaborated in detail via examples. CONCLUSIONS To attain the proper estimated sample sizes, the computation must satisfy the necessary premises which included the appropriate statistical analysis methods to be used.