Given prior work (Stephan et al., 2014; Westerhof et al., 2014), we hypothesized that feeling younger would be associated with markers of better cognitive and cardiovascular health, namely better memory performance and lower resting heart rate variability. Moreover, we hypothesized that these benefits would depend on relationship quality, such that a younger subjective age bias would be more strongly linked to better cognitive and cardiovascular health among adults in higher quality relationships.
Potential Implications for Cognitive Health.
First, we were interested in potential interactive effects on cognitive health, specifically memory performance. Memory performance has been examined in numerous studies of subjective age bias (e.g., Stephan et al., 2016), as well as in other studies of aging perceptions and attitudes. Memory performance is important for healthy aging given that it normatively declines with age and is a domain in which older adults face negative stereotypes. Although relationship quality has not, to our knowledge, been previously linked to memory declines with age, it could work interactively with a younger subjective age bias in this domain.
Potential Implications for Cardiovascular Health.
Second, we examined implications for cardiovascular health, specifically resting heart rate variability. Heart rate variability (HRV) captures the regularity of the length of intervals between heart-beats and reflects the flexibility of the autonomic nervous system to regulate cardiac activity (Appelhans & Luecken, 2006). Greater variability (higher HRV) has been associated with beneficial social, psychological, and physiological outcomes (Muhtadie, Koslov, & Mendes, 2015; Porges, 1995). Of particular relevance to this investigation, resting HRV has also been linked to prospective heart health. Decreases in resting HRV precede the onset of cardiovascular disease (e.g., hypertension; Schroeder et al., 2003; Tsuji et al., 1996), which made it an especially suitable measure of cardiovascular health to use in an age-diverse sample, such as the one we examined.
Method
We tested the hypothesized interactive effects of subjective age bias and relationship quality using data from the Midlife in the United States (MIDUS) study, a national study of adults residing in the United States (Brim, Ryff, & Kessler, 2004). Data to test our hypotheses came from MIDUS I (Wave 1), MIDUS II (Wave 2), the MIDUS Cognitive Project, and the MIDUS Biomarker Project. MIDUS I was conducted in 1995–1996 (n = 7108), MIDUS II (n = 4963) and the MIDUS Cognitive Project (n = 4512) were conducted in 2004–2006, and the MIDUS Bio.
In the current study, we used data from more than 600 participants (ages 34–84) who were married or in a marriage-like relationship who (a) reported their chronological age, subjective age, and the quality of their relationship with their spouse/partner in both waves and participated in the (b) Cognitive Project and (c) Biomarker Project. Overall, there were 678 unique participants who contributed data to at least one of the analyses presented below, and there were 567 participants https://getbride.org/sv/hollandska-kvinnor/ who contributed data to all of the analyses.
Procedure and Materials
MIDUS participants responded to questions about their felt age, relationship quality, and other demographic variables as part of a telephone interview. Memory performance was also assessed via telephone, as described below. Resting heart rate variability was measured during a laboratory visit at one of three sites across the United States.
Subjective Age.
In Waves 1 and 2, subjective age was assessed by asking participants “how old they felt most of the time.” Answers were reported in years. One observation from each wave fell more than 4 standard deviations above the mean; these observations were removed prior to analysis.
Relationship Quality.
In Waves 1 and 2, participants indicated the quality of their relationship with their spouse or partner (“Would you describe your relationship as…?”) using a scale ranging from 1 (Excellent) to 5 (Poor).