The daily pattern of heart rate, body temperature, and locomotor activity in guinea pigs

We studied the characteristics of the rhythmicity of heart rate (HR), body temperature (BT), and locomotor activity (LA) in conscious and unrestrained guinea pigs using a telemetry system. HR and/or LA in some guinea pigs cle arly showed circadian rhythms, but in others there were no significant dail y patterns; BT did not show significant daily rhythms. These results sugges t that guinea pigs might have different individual characteristics of rhyth micity, and we should, therefore, be careful when using guinea pigs in chro no-biomedical research. We believe that the results of this study may be us eful for future biomedical studies using guinea pigs.