Those paired with an opposite-sex partner exerciced a higher levels of intensity and traveled greater distances during their workouts; and even more if single

Going the distance, going for speed: Honest signaling and the benefits of exercising with an opposite-sex partner. Michael D. Baker et al. Evolution and Human Behavior,
https://doi.org/10.1016/j.evolhumbehav.2018.10.004

When people are aware that potential mates are observing their performances, they may alter their behavior (consciously or unconsciously) in order to make themselves appear more desirable to these individuals. This is consistent with previous research showing that matingrelated display strategies may be situationally sensitive, such that people will only engage in these displays when they believe that their performance will be viewed by a desirable functionally-relevant target (Baker & Maner, 2008, 2009).

In general, the current research demonstrates the utility of applying an evolutionary perspective to generate and test specific predictions regarding how human performance varies depending upon both fundamental social motives and social context. A more general social psychological theory such as social facilitation theory would generate a prediction that performance would be similarly enhanced in the presence of any partner, regardless of individual differences in relationship status or mating motives. However, our results demonstrate that performance in the presence of another individual varies depending on the sex of the individuals in the situation as well as the motives of the actor. We argue that this finding is best interpreted as being a product of human mating strategies. More specifically, the pattern of observed results is consistent with predictions generated by costly signaling theory and the fundamental social motives perspective. Improvements in performance were observed only in the presence of a potential mate and only when the actor possessed personal characteristics associated with greater levels of motivation to seek a mate. Accounting for individual differences in fundamental social motives and functionally relevant social factors can lead to the generation of novel hypotheses about how these factors interact to impact performance. Although the current research focused on exercise performance, it is reasonable to speculate that fundamental social motives and social context might interact to influence performance of a range of different behaviors in functionally relevant ways.

The findings of the current work demonstrate how social context can affect performance in a manner consistent with a sexual display strategy. By tailoring one’s behaviors to the preferences of potential mates, these behaviors can serve as advertisements of desirable qualities, allowing people to market themselves as desirable romantic or sexual prospects. In order to better understand why people behave the way that they do in any given situation, it is helpful to take into account the opportunities afforded by the social context as well as the fundamental social goals that the actor is motivated to pursue. This work demonstrates that conceptualizing public behaviors as serving a social display function can lead to an improved understanding of the impact of social context on performance.