This paper reports the results of two field studies which examined pos
sible changes in self-reported psychological mood with running. The pa
rticipants in both studies were regularly exercising male and female u
niversity students. In the first study, mood was monitored pre- and po
st-running sessions during a 7-week course designed to improve individ
ual levels of physical fitness. In a follow-up study, mood was measure
d pre- and post-running and subjects also made a number of colour choi
ces as an indication of arousal preference, as they ran. In addition,
subjects' times over a fixed distance were recorded and in both studie
s subjects were further subdivided into two groups: 'fast' and 'slow'
runners. The results from the first study indicated that, in spite of
the increasing demands of the running programme, subjects' mood experi
ence was generally pleasant, characterized by high arousal and low str
ess. In both studies, significant increases in male and female self-re
ported arousal scores pre- to post-running were obtained, along with n
on-significant increases in preferred arousal levels. When the mood re
sponse of fast runners was compared with that of slow runners, some si
gnificant findings with respect to self-reported arousal were observed
. Indicators of stress and arousal discrepancy pre- to post-running we
re low and mostly did not change significantly. Where significant chan
ges did occur, scores decreased significantly with running. The implic
ations of the findings for modulating arousal levels at work are discu
ssed.