Participation in regular physical activity has been shown to have a number of physical and psychological benefits for individuals' well-being. In particular, aerobic exercise has been shown to enhance mood, to combat mild depression and state anxiety, and to elevate self-esteem (Davis, 1990; Iannos & Tiggemann, 1997; Smolak, Murnen, & Ruble, 2000). However, these benefits have not been found in all samples. In young women, self-esteem and body satisfaction have actually been found to decrease with increasing amounts of exercise (Penas-Lledo, Sancho, & Waller, 2002; Tiggemann & Williamson, 2000). This may be because many women see exercise as a means of speeding up the weight loss process and adopt it as a primary strategy for altering body shape (Furnham, Badmin, & Sneade, 2002). Exercising for weight control, body tone, and attractiveness has in turn been associated with increased body dissatisfaction, disturbed eating, and lower body-esteem (Furnham et al., 2002; McDonald & Thompson, 1992; Silberstein, Striegel-Moore, Timko, & Rodin, 1988; Tiggemann & Williamson, 2000). In contrast, functional reasons for exercise such as health, enjoyment, or fitness have been associated with increased self-esteem and body-esteem, as well as lower levels of body dissatisfaction (Strelan, Mehaffey, & Tiggemann, 2003; Tiggemann & Williamson, 2000). Strelan et al. (2003) suggested that one plausible explanation for the observed associations between reasons for exercise, body-esteem, and disordered eating is offered by Objectification Theory (Fredrickson & Roberts, 1997).argues that being exposed to multiple forms of bodily objectification (such as sexual gaze) gradually makes women and girls come to see themselves as an "object" for others to view and evaluate on the basis of their appearance. Internalization of this observer's perspective is termed "self-objectification," and it is characterized by the habitual monitoring of one's outward appearance (Fredrickson & Roberts, 1997). Such self-objectification is related to a number of negative consequences including increased levels of appearance anxiety and body shame, decreased opportunities for peak motivational states or "flow," and a decreased awareness of internal bodily states. These negative consequences are thought to contribute to three psychological disorders experienced frequently by women: unipolar depression, sexual dysfunction, and eating disorders (Fredrickson & Roberts, 1997). There is now considerable support for the predictions of Objectification Theory as it pertains to eating disorders. Not only do self-objectification and self-surveillance predict disordered eating (Fredrickson et al., 1998; McKinley, 1998; McKinley & Hyde, 1996), but support has also been found for the mediational model whereby body shame and/or appearance anxiety mediate the relationship between self-objectification and disordered eating (Noll & Fredrickson, 1998; Tiggemann & Kuring, 2004; Tiggemann & Lynch, 2001; Tiggemann & Slater, 2001).

Although all Western women exist in an objectifying culture, not all women are equally affected by it. There are individual differences in women's experiences of self-objectification and its consequences. This is because certain situations or subcultures (viz. ones that draw attention to the body) intensify the likelihood of experiencing self-objectification (Fredrickson et al., 1998). For example, ballet dancers have been proposed as an at-risk group for self-objectification and disordered eating because of their intense focus on the body and appearance. Former ballet dancers have been found to score higher than nondancers on measures of self-objectification, self-surveillance, and disordered eating (Tiggemann & Slater, 2001).

Another environment with an increased focus on bodily appearance is fitness centers and the particular subculture of aerobics. This is the subject of the current study. The fitness center environment contains a large number of clearly objectifying features: multiple full-length mirrors, posters that idealize the female body, the opportunity for direct comparison with other women, scanty and revealingly aerobic clothing, and the presence of men observing women exercising. Thus, both aerobic instructors and participants are samples likely to score high on self-objectification. This is supported by the finding that young women who attend fitness centers self-objectify more than other general samples (Strelan et al., 2003). Strelan et al. (2003) also found that high self-objectification was associated with exercising for appearance-related reasons, whereas exercising for health/fitness was associated with lower self-objectification. The promotion by most fitness centers of bodily change through exercising for weight loss could further contribute to self-objectification. Thus, although exercise is generally related to positive effects on individuals' well-being, we hypothesized that the environment in which exercise is performed would moderate the level of self-objectification. Specifically, because of the number of objectifying cues within fitness centers, it was predicted that time spent exercising within the fitness center environment would be associated with higher levels of self-objectification than would time spent exercising outside of the fitness center environment.