Hello!

I am a new commuter, I have used my bike a few times over the past few weeks and this week I rode in/out of work 4 times clocking up 48 miles at around 12mph (my journey is around 12 miles). I doubled up one day and the next morning rode in so maybe that is the issue as my legs feel heavy (but not hurting), I just feel a bit tired. I cannot split my commute in any way and to be honest I find the distance enjoyable. Anyone got any tips on how to get used to the mileage so I can ride in and out of work most days of the week up to a max of 96 miles per week? Should I just do one way each day for a bit or double up (ride in then home) but have a rest day between until this feels easy and I don't have heavy legs? I can leave my bike securely at work which gives me options.

I should add my bike is being serviced this weekend as the gears have been slipping a lot and so the cables are stretched I am told so maybe my heavy legs could be resolved once I am able to select and keep(!) the correct gear.

I have on and off done a large amount of fitness work (hours every day) but before I started this all a month ago I had not done any serious fitness for over a year at least but I do build muscle very quickly and have low body fat, my cardio is almost non existent though so and that is what I am really keen on building, aerobic fitness.

Any advice/thoughts appreciated!