Table 2.
Participant data from study in normal weight and obese healthy volunteers
| Normal weight (n = 10) | Obese (n = 10) | P value | |
|---|---|---|---|
| Age (years) | 28.3 ± 2.1 | 28.2 ± 2.1 | 0.982 |
| Sex | 5 males, 5 females | 4 males, 6 females | |
| BMI (kg m−2) | 21.5 ± 0.4 | 36.2 ± 1.3 | 4.20 × 10−9 |
| Fat mass (kg) | 10.9 ± 1.1 | 38.1 ± 2.3 | 2.45 × 10−9 |
| Fat percentage (%) | 17.3 ± 2.0 | 35.8 ± 2.0 | 3.99 × 10−6 |
| Systolic blood pressure (mmHg) | 121 ± 3 | 129 ± 4 | 0.143 |
| Diastolic blood pressure (mmHg) | 72 ± 3 | 80 ± 3 | 0.069 |
| Outdoor temperature (°C) | 8.4 ± 1.4 | 7.3 ± 1.5 | 0.591 |
| Warm room temperature (°C) | 23.7 ± 0.3 | 23.5 ± 0.1 | 0.496 |
| Cold room temperature (°C) | 16.0 ± 0.2 | 16.1 ± 0.1 | 0.690 |
| Indirect calorimetry data | |||
| EE in warm (kcal d−1) | 1,477 ± 81 | 1,897 ± 101 | 0.004 |
| EE in cold (kcal d−1) | 1,635 ± 85* | 1,984 ± 84 | 0.009 *0.008 |
| CIT (kcal d−1) | 158 ± 47 | 86 ± 52 | 0.322 |
| Thermal imaging data | |||
| Supraclavicular skin temperature in warm (°C) | 35.4 ± 0.1 | 34.7 ± 0.1 | 6.18 × 10−4 |
| Supraclavicular skin temperature in cold (°C) | 34.4 ± 0.2 | 33.4 ± 0.2 | 8.40 × 10−4 |
| Sternal temperature in warm (°C) | 34.3 ± 0.2 | 33.6 ± 0.2 | 0.028 |
| Sternal temperature in cold (°C) | 32.7 ± 0.3 | 31.0 ± 0.3 | 0.002 |
| Cold-induced change in supraclavicular temperature (°C) | -1.0 ± 0.1 | -1.4 ± 0.2 | 0.061 |
| Cold-induced change in sternal temperature (°C) | -1.7 ± 0.2 | -2.6 ± 0.2 | 0.002 |
| Temperature differential between supraclavicular and sternum in warm (°C) | 1.1 ± 0.2 | 1.1 ± 0.2 | 0.788 |
| Temperature differential between supraclavicular and sternum in cold (°C) | 1.7 ± 0.3 | 2.4 ± 0.3 | 0.157 |
| Cold-induced change in temperature differential (°C) | 0.7 ± 0.1 | 1.2 ± 0.2 | 0.018 |
Data are mean ± s.e.m. for all 20 participants. The obese group had lower supraclavicular and sternal temperatures during both warm and cold conditions. Outdoor temperature was measured at 10 a.m. on the morning of each study visit. Comparisons between groups were performed using the unpaired t-test and between warm and cold exposure using the paired t-test. Significant P values are in bold. Cold exposure increased EE in the normal weight group (*P = 0.008) but not the obese group (P = 0.131).