We aim to investigate changes in objective measures of physical activity (PA) and sleep patterns one month before and during Ramadan among healthy fasting individuals. Twenty-two healthy individuals (Mean age= 23.09 ±7.95 years and mean BMI 24.92 ±4.42, and 50% of females) voluntarily participated in this observational study. Participants wore the ActiGraph activity monitor wGT3X-BT on the right hip for seven consecutive days (24 hrs./day), expect for bathing and swimming activities, during a month before and during the month of Ramadan. During the time of wearing, each participant completed sleep diary to subjectively track sleeping schedule. We used ActiLife 6.13.4 software to initialize, download, and analyzing PA and sleep data collected from wearing the activity monitor. A paired-samples t test indicated a significant increase in the average sedentary behavior during Ramadan from (1093 ±645 to 3367 ±1201 min/d; P<.001), a significant reduction in the average daily light activity during Ramadan from (119 ±63 to 37 ±47; P<.001), and a significant reduction in MVPA from (32.5 ±22.8 to 9.2 ±7.2 min/d; P<.001). Regarding sleep patterns, bedtime showed significantly different between before and during Ramadan (23:47 ±16 min vs 1:20 ±30 min, t = -3.01, p = 0.007), while there were not significant changes in waking time, sleep onset latency, total sleep time, and sleep efficiency. This study revealed that there were unfavorable significant changes in daily sedentary behavior, light activity, and moderate-to-vigorous activity during the month of Ramdan. This study found Ramadan fasting did significantly change the bedtime among the participants.