Manufacturers of telescoping trekking poles claim that using trekking poles promotes an upright posture, which enables more efficient use of lungs, however, there are scant data regarding the metabolic responses [heart rate (HR), energy expenditure (EE), and oxygen consumption (VO₂)] to hiking in the field with ambulatory aids such as trekking poles. The purpose of this study was to determine selected metabolic responses of males and females while hiking with and without bilateral trekking poles during a trail hike. Seven males and six females (age=22.8 ± 2.1 yr, ht=173.9 ± 10.9 cm, wt=71.4 ± 13.2 kg) were recruited to hike at a self-selected pace and intensity for two, 4-km trials in counter balanced design: trekking pole or no trekking pole conditions. The hiking trail ascended from 1510 m to 1860 m and returned to 1510 m. No significant mean differences existed in time to complete either the two hikes of 4 km in length consisting of 2 km uphill (9% grade) to the summit and 2 km downhill back to the starting point. Heart rate (b×min^-1) was measured using a Polar Vantage XL monitor and VO₂ (ml×kg^-1×min^-1) was recorded utilizing an Aerosport KB1-C portable metabolic analyzer. Repeated measures ANOVA found significantly different mean VO₂ responses [F (3, 27)=324.61, p < .001], EE responses [F (3, 27)=150.46, p < .001], and HR responses [F (3, 27)=51.59, p < .001]. Tukey post hoc tests identified that VO₂ uphill (38.7 vs. 34.9 ml×kg^-1×min^-1), VO₂ downhill (21.6 vs. 19.0 ml×kg^-1×min^-1), energy expenditure uphill (13.5 vs. 12.6 kcals×min^-1), energy expenditure downhill (7.2 vs. 6.5 kcals×min^-1), and HR downhill (130 vs. 125 b×min^-1), were significantly higher while hiking with bilateral trekking poles compared to non-pole conditions, respectively. These results indicate that hiking with bilateral trekking poles poses a greater metabolic demand on the body compared to hiking without the poles. The increased metabolic cost is likely due to increased exercise muscle mass by employing the upper body. This study provides field evaluation of the metabolic effects of using bilateral trekking poles while hiking over varied terrain.