Assessment of the reproducibility of a mental stress test as a first step to its use in drug research

Mental stress tests are frequently used in drug research. However, the reproducibility of the test is largely unknown particularly after repeated performance. Eight healthy volunteers performed mental arithmetic for 6 min (mental stress test) on 2 occasions separated by 14 days (during morning and afternoon session). During the tests, heart rate (HR) and systolic (SBP) and diastolic blood pressure (DBP) were determined on a beat-to-beat basis. Before testing baselines of BP and HR were assessed over one minute intervals. Data are shown as means ± SD and comparisons were made using paired Student's t-tests. Baseline values and responses to mental stress are summarised in the table. Baseline HR was lower in the morning than in the afternoon on both occasions, but was not different between occasions. Baseline DBP values were lower during the second occasion, but no circadian variation was noted. No differences in SBP were observed. Except for a slightly higher HR response at the first test performance, no differences were found for the reponses to mental stress. (See Table) Although baseline values for HR were different in the morning and afternoon, responses to mental stress were similar, except for a slightly higher response at the first test, which may reflect some habituation to the test with regard to HR. Thus, the response to mental stress appeared reproducible over multiple test sessions and may be a suitable tool to be used in drug research. Clinical Pharmacology & Therapeutics (2004) 75, P54–P54; doi: 10.1016/j.clpt.2003.11.204 Table 1.    Occasion 1 Occasion 2   a.m. p.m. a.m. p.m. * p<0.05 between occasion 1 and 2. # p<0.05 between a.m. and p.m. baseline HR 66 ± 6 73 ± 6# 65 ± 5 72 ± 7# HR response 21 ± 6 17 ± 6 15 ± 4* 16 ± 6 baseline SBP 128 ± 20 121 ± 14 114 ± 14 115 ± 13 SBP response 12 ± 9 14 ± 11 18 ± 12 11 ± 8 baseline DBP 76 ± 13 68 ± 7 64 ± 7* 62 ± 6* DBP response 11 ± 6 11 ± 7 14 ± 8 10 ± 5