Academic journal article Research Quarterly for Exercise and Sport

Effect of Exercise Training on Hippocampal Volume in Humans: A Pilot Study

Academic journal article Research Quarterly for Exercise and Sport

Effect of Exercise Training on Hippocampal Volume in Humans: A Pilot Study

Article excerpt

Key words: hippocampus, MRI, structure

The hippocampus is the primary site of memory and learning in the brain. Both normal aging and various disease pathologies (e.g., alcoholism, schizophrenia, and major depressive disorder) are associated with lower hippocampal volumes in humans (Agartz, Momenan, Rawlings, Kerich, & Hommer, 1999; Barta, Dhingra, Royall, & Schwartz, 1997;Jemigan et al., 2001; McKinnon, Yucel, Nazarov, & MacQueen, 2009; Meisenzahl et al., 2009), and hippocampal atrophy predicts progression of Alzheimers disease (Henneman et al., 2009). In animals, there is convincing evidence that exercise training increases hippocampal volume (Van der Borght, Havekes, Bos, Eggen, & Van der Zee, 2007; van Praag, Shubert, Zhao, & Gage, 2005;). A recent cross-sectional study in older humans demonstrated a positive relation between aerobic fitness and hippocampal volume (Erickson et al., 2009). Moreover, a recent study found that a year of aerobic exercise training increases hippocampal volume by 2% in older adults (Erickson et al., 2011). Accordingly, in the current preliminary study we sought to confirm the direct effect of supervised exercise training on magnetic resonance imaging (MRI) estimates of hippocampal volume in healthy humans.

Method

Thirteen men (n = 8) and women (n = 5) completed this study, which was approved by the hospital's Institutional Review Board. Participants gave informed consent, and the study was conducted in agreement with guidelines set forth by the Declaration of Helsinki. Participants were healthy, nonsmoking adults (Mage = 34 years, SD = 9; age range = 23-45 years) who seldom exercised and had no reported chronic diseases, as assessed by medical history, physical exam, and symptom-limited, physician-supervised exercise stress test (Bruce treadmill test; American College of Sports Medicine, 2006). Baseline intellectual quotient (IQ) estimate (Wechsler Adult Intelligence Scale block design and vocabulary; Wechsler, 1997), Beck Depression Inventory (BDI; Beck, Ward, Mendelson, Mock, & Erbaugh, 1961) and Mini-Mental-State Exam (MMSE; Folstein, Folstein, & McHugh, 1975) were normal (all participants had scores of IQ> 80, BDI < 10, and MMSE > 24). Participants were not taking medications known to affect cardiovascular, cognitive, or brain function, such as those for depression, hypertension, hormone therapy, hypercholesterolemia, or anxiety, and dietary supplements, such as phosphatidylserine or ginkgo biloba (Kennedy, Haskell, Mauri, & Scholey, 2007).

An exercise trainer supervised participants' exercise 3 days/week for 10 weeks. Exercise consisted of walking or running on a treadmill. The duration of each exercise session was progressively increased from 15 to 45 min during the first 5 weeks. Participants exercised at between 60-85% of their predetermined maximal heart rate to regulate exercise intensity. Once participants were able to perform 45 min of aerobic exercise (not including warm up and cool down), they continued this level of exercise 3 days/week for the remaining 5 weeks. Prior to and following exercise training, participants performed a graded exercise test to maximal exertion using the modified Balke protocol (American College of Sports Medicine, 2006). Expired gases were analyzed with a Parvomedics TrueOne 2400 metabolic cart (ParvoMedics Corp., Sandy, UT) to assess maximal oxygen uptake (V[O.sub.2]max). Prior to each exercise test, anthropometric measures (height and weight), resting blood pressure, and resting heart rate were recorded. Twelve participants were also administered a test of psychological well being (Psychological General Well-Being Index; Dupuy, 1984).

On a separate study day before and after (within 3 days of finishing) the exercise training protocol, participants' hippocampal volume and performance on a memory-based task (Figural Memory Test) was assessed at the Olin Neuropsychiatry Research Center at the Institute of Living, Hartford Hospital. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.