I wear a fitbit heart rate thing to bed its showing my heart rate goes as low as 42 while sleeping it worries me bc im not and athlete im 27 weigh 180?

Slow heart rate: It is common and normal for heart rate to slow during sleep. Unless there are other things to make you worry about a slow heart rate (such as fatigue or shortness of breath doing exercise, or dizziness or fainting) I would not worry about this. If you want specific guidance, consider getting a cardiology consult here on HealthTap.