During hypoglycemia, cerebral blood flow (CBF) does not increase significantly until peripheral glucose levels are very low (2.0 mmol/l), that is, well below the blood glucose threshold for impairment of cognitive function (3.0 mmol/l). Because increased rates of cerebral blood flow will increase glucose transport, a failure of flow to rise earlier, before brain function is threatened, might be considered maladaptive. To examine the influence of inducing an earlier rise in CBF during hypoglycemia, eight healthy volunteers participated in three studies using a randomized, placebo-controlled design. In all three studies, a hyperinsulinemic (60 mU x m2 x min(-1)) clamp was used to maintain blood glucose levels at 4.5 mmol/l for 60 min. Thereafter, for EUG-ACZ, blood glucose was maintained at 4.5 mmol/l from 60 to 170 min and at 90 min from the start of this study, and 1-g acetazolamide i.v. was given to induce an early rise in CBF; for HYPO-ACZ, glucose was lowered over 20 min to 2.8 mmol/l and kept at that level for 90 min, and acetazolamide was given 90 min from the start of this study; and for HYPO-CON, glucose was treated as in HYPO-ACZ, and matching placebo was given in place of acetazolamide. Injection of acetazolamide was associated with a 30% rise in right (95% CI 24-34%) and left (20-32%) middle cerebral artery velocity (an index of CBF) during euglycemia without any change in hypoglycemia awareness or counterregulatory hormone levels. When glucose was lowered to 2.8 mmol/l, acetazolamide caused a similar rise in middle cerebral artery velocity in the HYPO-ACZ study. However, all subjects were less "aware" of hypoglycemia, had fewer adrenergic symptoms (sweating, palpitations, tremors; all P < 0.05), and had lower plasma epinephrine levels (1,026 vs. 1,790 pmol/l; -764 [437 to 1,097] pmol/l, point estimate of difference [95% CI]; P < 0.001), compared with the HYPO-CON study, whereas levels of other counter-regulatory hormones and norepinephrine were similar. Cognitive function (latency of the P300 evoked response) was unaffected by increasing CBF. In conclusion, enhanced rates of cerebral blood flow at the onset of systemic hypoglycemia are associated with diminished perception of low blood glucose levels and attenuation of the epinephrine counterregulatory response. These findings suggest that augmenting cerebral blood flow leads to an enhanced rate of substrate delivery to the central nervous system.

Background Despite the popularity of dating apps, there remain scarce data on the motivations, consequences and their influence on sexual behaviour change in the Australian population. Objective To explore motivations, dating app relationships, unintended consequences and change in sexual behaviour in dating app users at an Australian music festival. Methods A cross-sectional study design was used. Festival patrons aged 18–30 at a major Australian music festival completed a paper-based survey. Logistic regression was used to identify which factors were associated with an increase in sexual partners since using dating apps. Results The primary reasons for dating app use (N = 437) were boredom (59.7%), casual sex (45.1%) and casual dating (42.8%). A third of users used them at music festivals (33.8%, n = 432). A third of participants had used dating apps for more than 2 years (33.3%) and a third (33.0%) of users claimed to have changed their sexual behaviour after app use, including increased frequency of sexual activity (70.0%), number of sexual partners (57.1%) and sexual experimentation (42.1%). Dating app users tended not to discuss sexually transmitted infections (STI) status with a sexual partner regardless of whether they had met them on an app or not: 38.5% would ‘never’ and 36.9% would ‘sometimes’ have safe sex discussions with partners met via apps. Condoms were ‘always’ used for 36.9% of dating app users when meeting partners via dating apps, compared to 29.9% met by other means. 8.6% of dating app users reported having contracted STIs, and 2.8% had unwanted pregnancies with those met on dating apps. After adjusting for socio-demographics, those who had an STI after engaging in sexual activity with a person met via a dating app had 2.4 times the odds of reporting an increase in sexual partners, and those who had used a dating app for over 2 years had twice the odds of reporting an increase in sexual partners. When condom use was entered into the model, those that ‘often’ or ‘sometimes’ used a condom with a new dating app partner were twice as likely to report an increase in sexual partners since using dating apps, compared to those who ‘always’ used a condom with a new dating app partner. Sexual orientation and STI discussions with a new sexual dating app partner were not associated with an increase in dating app partners. Conclusion Dating app usage is common and users report increased sexual activity, sexual partners and experimentation. STI discussions with potential partners and condom use remained low regardless of how partners were met and despite an increase in sexual partners since using dating apps. Given the high-risk nature of individuals that utilise dating apps, safe sex discussion, including STIs, pregnancies and condom use should be promoted to improve sexual health outcomes.

Background Despite the prevalent use of geosocial networking dating apps (GNDAs), there is limited research on their impact on sexual health outcomes among young music festivals attendees. Objective This study aims to explore the use of GNDAs and risky sexual behaviors of young adults attending a music festival. Methods The music festival attendees (N=862) completed a cross-sectional questionnaire study encompassing demographics, dating app use, and risky sexual behaviors in the past year. Associations between these variables were estimated using bivariate and multivariate logistic regression analyses. Results Of the respondents, 51.9% (448/862) had used GNDAs in the previous year. Compared with people who had 1 partner, people who had 2-5 sexual partners in the previous year had almost 7 times the odds of using dating apps (odds ratio [OR] 6.581, 95% CI 4.643-9.328) and those who had more than 5 partners had 14 times the odds of using dating apps (OR 14.294, 95% CI 8.92-22.906). Condom users were more likely to be app users (P<.001), as were those who relied on emergency Plan B (P=.002), but people using hormonal contraception were less likely to use dating apps (P=.004). After adjusting for sexual orientation and relationship status, those having casual sex had 3.096 (95% CI 2.225-4.307; P<.001) times the odds of using dating apps and those having multiple sexual partners had 3.943 (95% CI 2.782-5.588; P<.001) times the odds of using dating apps. Similarly, after adjusting for sexual orientation, relationship status, and number of sexual partners, people who had no discussions before having sex about sexually transmitted infections (STIs) or boundaries were more likely to use dating apps (OR 1.755, 95% CI 1.232-2.500; P=.002). Those who perceived the risk of having sex without contraception to be very high had 2.486 (95% CI 2.213-5.096; P=.01) times the odds of using dating apps than those who perceived no risk. Compared with those who perceived no risk, people who thought that the risk of having multiple sexual partners was low to high had 1.871 (95% CI 1.024-3.418; P=.04) times the odds of using dating apps. A significant number of app users (389/440, 88.4%) indicated that GNDAs should promote safe sex. Conclusions This study identified that festival goers engaging in certain high-risk sexual behaviors, including casual sex, having multiple sexual partners, and having sex without discussion about STI status and boundaries, are more likely to use dating apps. Festival goers who perceived sex without any form of contraception, having sex while drunk, and having multiple sexual partners as risky were more likely to be app users. Policy makers and GNDA developers should acknowledge the vulnerability of their users to adverse sexual health outcomes and use GNDAs as a platform to promote risk-reduction practices.

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