Table 2.

Exercise performance during cardiopulmonary exercise testing by frailty group

Variable	Fried Frailty Phenotype			p for trend
	Not frail (score 0–1)	Intermediate (Score 2–3)	Frail (Score 4)
Workload,Watts	75 ± 27	38 ± 23	19 ± 17	<0.001
Workload % predicted	47 ±18	31± 18	14 ± 11	0.002
${\dot{\mathrm{V}}\mathrm{O}}_2$, mL/kg/min	19.7 ± 6.6	13.4 ± 4.1	9.9 ± 2.4	<0.001
${\dot{\mathrm{V}}\mathrm{O}}_2$ % predicted, %	70 ± 19	49 ± 14	35 ± 7	<0.001
${\dot{\mathrm{V}}\mathrm{O}}_2$/Work rate slope, % predicted†	133 ± 36	139 ± 66	190 ± 124	0.54
SpO2,%	92 ± 4	92 ± 6	94 ± 5	0.93
${\dot{\mathrm{V}}}_{\mathrm{E}}$/ ${\dot{\mathrm{V}}\mathrm{CO}}_2$ slope, % predicted	115 ± 44	113 ± 44	123 ± 74	0.95
End tidal CO2,mmHg/min	38.0 ± 8.9	38.7 ± 9.7	38.4 ± 9.5	0.88
Breathing reserve, %	32 ± 4	22 ± 3	19 ± 7	0.04
${\dot{\mathrm{V}}}_{\mathrm{E}}$, L/min	60.0 ± 18	34.5 ± 16	27.3 ± 18	<0.001
${\dot{\mathrm{V}}}_{\mathrm{T}}$, % predicted	63 ± 25	54 ± 19	51 ± 27	0.051
SBP, mmHg	165 ± 20	160 ± 18	143 ± 17	0.12
Heart rate reserve %	80 ± 9	71 ± 11	69 ± 9	0.001
HR/ ${\dot{\mathrm{V}}\mathrm{O}}_2$ slope % predicted	81 ± 30	84 ± 43	103 ± 50	0.43

${\dot{\mathrm{V}}\mathrm{O}}_2$: peak volume of oxygen utilized, ${\dot{\mathrm{V}}\mathrm{O}}_2$/Work rate slope: increase in oxygen utilization per watt, SpO₂: oxygen saturation by pulse oximetry, ${\dot{\mathrm{V}}}_{\mathrm{E}}$/V’CO₂ slope: ventilatory equivalent for carbon dioxide slope, ${\dot{\mathrm{V}}}_{\mathrm{E}}$, L/min: minute ventilation, ${\dot{\mathrm{V}}}_{\mathrm{T}}$: tidal volume, SBP: Systolic Blood Pressure, HR/ ${\dot{\mathrm{V}}\mathrm{O}}_2$ slope: increase in heart rate per liter of oxygen utilized. Heart rate reserve %, a normal exercise response is to attain ≥80% of one’s heart rate reserve.

^†n=64, two participants could not exercise beyond the warm up period, therefore workload never increased and ${\dot{\mathrm{V}}\mathrm{O}}_2$/work rate slope could not be obtained.

CPET parameters are an average of the last 20 seconds of peak exercise, with the exception of the ${\dot{\mathrm{V}}\mathrm{O}}_2$/Work rate slope and ${\dot{\mathrm{V}}}_{\mathrm{E}}$/ ${\dot{\mathrm{V}}\mathrm{CO}}_2$ slope, which are measured from the onset of ramping to the last breath at the end of ramping.