Sweaty times on the treadmill

stats of the week: run 56km, gym 2hrs

Back to a sufficient mileage I included treadmill intervals to my schedule - as I do in December usually. Looking at the time table below, my speed might seem to be too low. I've been doing this for more than a decade and I learnt that my heartrate is 10 beats higher on the treadmill compared to outside workouts. Experience says that this sort of speed will get me fit for New Year's Eve Race and I always was able to run at a 4:30 min/km pace for 15K. But I doubt I can do it again as I got older by one year again.

from km	to km	kmh	min/km	time
0,0	0,2	3,5	17:09	03:26
0,2	0,6	8,5	07:04	06:15
0,6	1,0	9,0	06:40	08:55
1,0	1,5	9,5	06:19	12:05
1,5	2,0	10,0	06:00	15:05
2,0	2,5	12,0	05:00	17:35
2,5	3,0	12,5	04:48	19:59
3,0	3,5	8,5	07:04	23:30
3,5	4,0	12,0	05:00	26:00
4,0	4,5	12,7	04:43	28:22
4,5	5,0	8,5	07:04	31:54
5,0	5,5	12,0	05:00	34:24
5,5	6,0	13,0	04:37	36:42
6,0	7,0	7,0	08:34	45:17
7,0	7,5	12,0	05:00	47:47
7,5	8,0	12,7	04:43	50:08
8,0	8,5	8,5	07:04	53:40
8,5	9,0	12,0	05:00	56:10
9,0	9,5	13,0	04:37	58:29
9,5	10,0	8,5	07:04	1:02:00
10,0	10,5	12,0	05:00	1:04:30
10,5	11,0	12,7	04:43	1:06:52
11,0	12,0	8,5	07:04	1:13:56