Improved exercise performance and increased aerobic capacity after endurance training of patients with stable polymyositis and dermatomyositis

Table 2 Lower maximal oxygen uptake and endurance performance in myositis patients compared to healthy controls.

	Patients n= 23 Mean ± SD	Healthy Controls n= 12 Mean ± SD	Unpaired t-test
VO₂ max test
VO₂ max (l min^-1)	1.65 ± 0.51	2.28 ± 0.55	P <0.01
VO₂, max/body weight (ml min^-1 kg^-1)	22 ± 5	32 ± 6	P <0.01
Power at VO₂ max (W)	120 ± 36	185 ± 38	P <0.001
Respiratory exchange ratio(RQ = CO₂/O₂)	1.1 ± 0.1	1.2 ± 0.1	n.s.
Maximum heart rate (min^-1)	160 ± 15	173 ± 16	n.s.
Borg rating (6 to 20):
Peripheral exertion	19 ± 1	19 ± 1	n.s
Central exertion	17 ± 3	18 ± 2	n.s.
Endurance cycling test
Time to exhaustion (minute)	14.0 ± 5.1	26.1 ± 11.3	P <0.001
Lactate (mM)	10.6 ± 3.6	11.7 ± 3.7	n.s.
Percentage maximum heart rate	91 ± 1	96 ± 1	n.s.
Borg rating (6 to 20):
Peripheral exertion	19 ± 1	18 ± 2	n.s
Central exertion	17 ± 1	18 ± 2	n.s

n.s., Non-significant; VO₂ max, maximal oxygen uptake; endurance cycling test, time cycling to exhaustion performed with a constant power, which in each individual was set to requiring 65% of baseline VO₂ max; Borg rating, rating of exertion at end of VO₂ max test and at the end of the endurance cycling test; Lactate, concentration of lactate measured in muscle vastus lateralis with microdialysis directly after the endurance cycling test.

ISSN: 1478-6362