Rest Day -- Ride Bike for 20 Miles

I used to bike only 12 miles. And I felt tired as well
after 20 miles. That's very good. Right?

Split	Time	Distance	Avg Pace
Summary	1:40:27.0	20.17	4:59
1	5:06.4	1.00	5:06
2	4:45.8	1.00	4:46
3	4:55.1	1.00	4:55
4	5:31.1	1.00	5:31
5	5:00.5	1.00	5:01
6	4:48.2	1.00	4:48
7	5:04.3	1.00	5:04
8	4:46.3	1.00	4:46
9	4:50.7	1.00	4:51
10	5:02.9	1.00	5:03
11	4:27.7	1.00	4:28
12	4:29.6	1.00	4:30
13	4:26.9	1.00	4:27
14	5:10.1	1.00	5:10
15	4:59.0	1.00	4:59
16	5:14.3	1.00	5:14
17	5:22.7	1.00	5:23
18	5:09.8	1.00	5:10
19	5:07.7	1.00	5:08
20	4:58.9	1.00	4:59
21	1:10.9	0.17	6:57