If you tap on a metric on your Dashboard this will open a more detailed analysis that will give you a chart of that metric displayed over time. This gives you more information than the cumulative totals displayed on the dashboard for longer timeframes, giving you a better overview of trends and improvements.
Inside of this menu you can select different timeframes for analysis from the same menu bar available to show various cumulative totals. This total at the top of the screen gives you options for weekly, monthly, and yearly graphing of values, as well as for the last 7 days, last 30 days, last 365 days or any other custom timeframe.
Metric details are available for any data that is entered into Apple Health including, but not limited to: heart rate, weight, workout time, blood pressure and more.