Activation in novice and expert parachutists while jumping

Analysis of the Objective Internal Load in Portuguese Skydivers in the First Jump of the Day

The general objective of this study was to identify the variation in heart rate (HR) of Portuguese skydivers during 6 moments in their first jump of the day, bearing in mind the variable level of experience. Thirty-one Portuguese skydivers, 28 men and 3 women, aged between 19 and 62, participated in the study, 12 had A and B licenses (less experienced) and 19 had C and D licences (more experienced). The instrument used to record the heart rate of the skydivers at the different moments of their first jump of the day was the WIMU PRO. A repeated measures analysis of variance was used to analyse HR at different moments in the jump and its relation with the variables level of experience. Bonferroni multiple comparisons were performed to study the importance of the differences observed in HR at the different moments. The effect size was evaluated with partial eta squared. The results showed that average HR in this group of skydivers was 130 bpm, in the different moments of the jump. HR increases from the value recorded at rest until the moment of jumping from the plane and opening the parachute, reaching the highest average at that moment, then decreasing until contact with the ground. Comparing the variable, we found that the less experienced had higher HR than the more experienced at all moments during the jump. Statistically significant differences were found at the different moments of the jump, regarding HR (Max: p < 0.001, ƞ2p = 0.820; Min: p < 0.001, ƞ2p = 0.821; AVG: p < 0.001, ƞ2p = 0.834) Level of experience with jumping moment interaction, we only verified differences related to HR Min (p = 0.007, ƞ2p = 0.056),. With regard to experience, the identified differences were not statistically significant. Skydiving triggers an acute adaptive cardiovascular response which is reflected in the increase in the HR, between the moment of boarding the plane and the moment at which the parachute opens, thereafter decreasing until contact with the ground. The most experienced parachutists recorded the highest HR at the moment of landing and the least experienced at the moment of free fall.

Performance anxiety and the plasticity of emotional responses

Current psychological theories of performance anxiety focus heavily on relating performers' physiological and mental states to their abilities to maintain focus and execute learned skills. How task-specific expertise and past experiences moderate the degree to which individuals become anxious in a given performance context are not well accounted for within these theories. This review considers how individual differences arising from learning may shape the psychobiological, emotional, and cognitive processes that modulate anxious states associated with the performance of highly trained skills. Current approaches to understanding performance anxiety are presented, followed by a critique of these approaches. A connectionist model is proposed as an alternative approach to characterising performance anxiety by viewing performers' anxious states at a specific time point as jointly determined by experience-dependent plasticity, competition between motivational systems, and ongoing cognitive and somatic states. Clarifying how experience-dependent plasticity contributes to the emergence of socio-evaluative anxiety in challenging situations can not only help performers avoid developing maladaptive emotional responses, but may also provide new clues about how memories of past events and imagined future states interact with motivational processes to drive changes in emotional states and cognitive processing.

Experience modulates the psychophysiological response of airborne warfighters during a tactical combat parachute jump

We aimed to analyse the effect of experience level in the psychophysiological response and specific fine motor skills of novel and expert parachute warfighters during a tactical combat parachute jump. We analysed blood oxygen saturation, heart rate, salivary cortisol, blood glucose, lactate and creatinkinase, leg strength, isometric hand-grip strength, cortical arousal, specific fine motor skills and cognitive anxiety, somatic anxiety and self-confident before and after a tactical combat parachute jump in 40 warfighters divided in two group, novel (n=17) and expert group (n=23). Novels presented a higher heart rate, lactate, cognitive anxiety, somatic anxiety and a lower self-confident than experts during the jump. We concluded that experience level has a direct effect on the psychophysiological response since novel paratroopers presented a higher psychophysiological response than compared to the expert ones, however this result neither affected the specific fine motor skills nor the muscle structure after a tactical combat parachute jump.

Experience, cortisol reactivity, and the coordination of emotional responses to skydiving

Physiological habituation to laboratory stressors has previously been demonstrated, although the literature remains equivocal. Previous studies have found skydiving to be a salient naturalistic stressor that elicits a robust subjective and physiological stress response. However, it is uncertain whether (or how) stress reactivity habituates to this stressor given that skydiving remains a risky, life-threatening challenge with every jump despite experience. While multiple components of the stress response have been documented, it is unclear whether an individual’s subjective emotions are related to their physiological responses. Documenting coordinated responsivity would lend insight into shared underlying mechanisms for the nature of habituation of both subjective (emotion) and objective (cortisol) stress responses. Therefore, we examined subjective emotion and cortisol responses in first-time compared to experienced skydivers in a predominantly male sample (total n = 44; males = 32, females = 12). Hierarchical linear modeling (HLM) revealed that experienced skydivers showed less reactivity and faster recovery compared to first-time skydivers. Subjective emotions were coordinated with physiological responses primarily within first-time skydivers. Pre-jump anxiety predicted cortisol reactivity within first-time, but not experienced, skydivers. Higher post-jump happiness predicted faster cortisol recovery after jumping although this effect overlapped somewhat with the effect of experience. Results suggest that experience may modulate the coordination of emotional response with cortisol reactivity to skydiving. Prior experience does not appear to extinguish the stress response but rather alters the individual’s engagement of the HPA axis.

Heart rate variability and critical flicker fusion frequency changes during and after parachute jumping in experienced skydivers

PURPOSE

The purpose of this study was (1) to further explore the heart rate dynamics and assess a potential cardiovascular risk in response to 4000 m jumps in experienced skydivers; (2) to assess whether there is an impact of such jumps on skydivers' cortical arousal or not, which may impact their decision making processes.

METHOD

18 experienced skydivers performed successive jumps from a plane at 4000 m of height. Heart rate dynamics and cortical arousal were assessed by the use of heart rate variability and Critical Flicker Fusion Frequency (CFFF), respectively.

RESULTS

CFFF did not differ between the three measurement time points (p > 0.05). Mean heart rate increased during the jump (p < 0.001) and came back to pre-jump values after the jump (p < 0.001). Percentage of the differences of successive NN intervals greater than 50 ms (pNN50) decreased during the jump (p < 0.001) and kept lower values after the jump compared to pre-jump (p < 0.05). High-frequency power (HF) did not differ during the jump (p > 0.05) but decreased after the jump compared to both pre-jump (p < 0.01) and jump (p < 0.05). Sample entropy decreased during the jump (p < 0.001) and came back to pre-jump values after the jump (p > 0.05).

CONCLUSION

These results confirm a vagal input reduction associated with a rise of the sympathetic tone during the jump and suggests that the experienced skydiver is not exposed to a high cardiovascular risk. This study also shows that environmental stresses induced by free fall could not hamper the perceptual vigilance of experienced skydivers.

Glucose changes and working memory in individuals with type 1 diabetes during air pressure changes simulating skydiving

BACKGROUND

Several countries restrict individuals with type 1 diabetes mellitus (T1DM) from skydiving because of concerns over possible alterations in consciousness. To our knowledge, glucose levels and working memory in individuals with T1DM during skydiving have not been assessed earlier. The objective of this study was to investigate changes in glucose levels and working memory in selected subjects with T1DM compared with control subjects without diabetes mellitus (DM) during ambient air pressure changes as those anticipated during standard skydiving.

SUBJECTS AND METHODS

Six subjects with T1DM and six controls were included. Using a hypobaric chamber, the ambient air pressure was changed to simulate a standard skydive from 4,000 m (13,000 feet) above mean sea level. The procedure was repeated six times to mimic a day of skydiving activity with a median of 8.7 h/day (5(th), 95(th) percentile: 8.1, 9.8 h). All subjects carried a continuous glucose monitor (CGM). Capillary glucose tests were taken in order to calibrate the CGM. Hemoglobin oxygen saturation, heart rate, and working memory, evaluated through digit span, were monitored regularly.

RESULTS

No subject experienced documented symptomatic hypoglycemia with impaired working memory during the simulations. One asymptomatic hypoglycemia episode with a plasma glucose level of <3.9 mmol/L was recorded in a subject with T1DM, with a corresponding CGM trend indicating declining glucose levels. Interstitial glucose levels of <3.9 mmol/L were recorded by CGM in three of the controls during the simulations. There were no significant differences in hemoglobin oxygen saturation, heart rate, or working memory between the T1DM patients and the controls.

CONCLUSIONS

This study of interstitial glucose levels and working memory could not show the activity-specific risk factor (i.e., repetitive rapid-onset hypobaric hypoxia exposures) to be a greater safety concern for selected subjects with T1DM compared with subjects without DM during a simulated day of skydiving. Further studies are needed to clarify the suitability of subjects with T1DM to participate in this air sport.

State anxiety and cortisol reactivity to skydiving in novice versus experienced skydivers

Previous studies have suggested that skydiving, a naturalistic stressor, is associated with increases in self-reported stress, anxiety and cortisol levels. However, it has not been established whether this stress reactivity is altered as a function of repeated exposure to skydiving. This is of interest due to previous observations that cortisol reactivity becomes habituated with repeated exposure to laboratory stressors, however, few studies have investigated such habituation to naturalistic stressors. State anxiety and cortisol reactivity to skydiving were measured in 11 first-time skydivers and 13 experienced skydivers (≥30 jumps, mean jumps=397.6), who were to complete a solo skydive. The novice skydivers reported significantly greater levels of state anxiety prior to the jump; however, there were no differences in pre-jump levels of salivary cortisol. Both groups exhibited significantly elevated salivary cortisol levels immediately post-jump, relative to i) pre-jump and ii) recovery. However, the two groups were indistinguishable with regard to their cortisol reactivity to the skydive. These findings support previous research demonstrating that skydiving elicits acute cortisol activation. Further, they suggest that i) cortisol reactivity does not habituate in experienced jumpers, and ii) that there is lack of concordance between self-reported levels of anxiety and biological stress reactivity in experienced skydivers.

Intolerance of uncertainty and decisions about delayed, probabilistic rewards

Worry is the inflated concern about potential future threats and is a hallmark feature of generalized anxiety disorder. Previous theoretical work has suggested that worry may be a consequence of intolerance of uncertainty (IU). The current study seeks to explore the behavioral consequences of IU. Specifically, we examine how IU might be associated with aspects of reward-based decision making. We utilized a simple laboratory gambling task in which participants chose between small, low-probability rewards available immediately at the beginning of each trial and large, high-probability rewards only available after some variable delay. Results demonstrate that higher levels of intolerance of uncertainty were associated with a tendency to select the immediately available, but less valuable and less probable rewards. IU also predicted decision-makers' sensitivity to outcomes. We discuss the cognitive and affective mechanisms that are likely to underlie the observed decision-making behavior and the implications for anxiety disorders.

Let's Talk About Race, Baby! When Whites' and Blacks' Interracial Contact Experiences Diverge

The present study investigated whether the conditions that make interracial contact anxiety-provoking for Whites differ from those that make it anxiety-provoking for Blacks. Specifically, the present work examined interracial anxiety as a function of discussant race (i.e., White or Black) and discussion topic (i.e., race-related or race-neutral). To that end, we examined the non-verbal behavior of White and Black participants during brief interpersonal interactions. Consistent with previous research, White participants behaved more anxiously during interracial than same-race interactions. Additionally, White participants of interracial interaction behaved more anxiously than their Black interaction partners. Furthermore, whereas White participants of interracial interactions found race-related discussions no more stressful than race-neutral discussions, Black participants of interracial interactions found race-related discussions less stressful than race-neutral discussions. The implications of these racial and contextual differences in interracial anxiety for improving interracial contact and race relations, more broadly, are discussed.

Exposure to heights in a theme park: fear, dizziness, and body sway

Fear of heights results in the experience of dizziness and measurable body sway. We investigated the relationship between fear, dizziness, and body sway during height exposure 16 m above ground. Thirty five healthy participants stood on a force-plate to measure sway before, during, and after exposure and an ECG was recorded. Self-report measures were anticipated fear and dizziness before exposure, as well as actual fear and dizziness during the three situations. For all participants, fear, dizziness, and body sway were increased during exposure. Anticipated fear most reliably predicted body sway during exposure. In addition, persons scoring high on trait fear of heights anticipated and experienced more fear during exposure, but this relationship was not found for any objective measure. There was no evidence that vestibular function moderates the relationship between sub-clinical fear and body sway. The results underline the importance of cognitive factors, like anticipatory anxiety and overestimation of bodily symptoms, in fear of heights.

Are Current Theories of Panic Falsifiable?

The authors examine 6 theories of panic attacks as to whether empirical approaches are capable of falsifying them and their heuristic value. The authors conclude that the catastrophic cognitions theory is least falsifiable because of the elusive nature of thoughts but that it has greatly stimulated research and therapy. The vicious circle theory is falsifiable only if the frightening internal sensations are specified. The 3-alarms theory postulates an indeterminate classification of attacks. Hyperventilation theory has been falsified. The suffocation false alarm theory lacks biological parameters that unambiguously index dyspnea or its distinction between anticipatory and panic anxiety. Some correspondences postulated between clinical phenomena and brain areas by the neuroanatomical hypothesis may be falsifiable if panic does not depend on specific thoughts. All these theories have heuristic value, and their unfalsifiable aspects are capable of modification.

Real-Life Stress and Opioid-Mediated Analgesia in Novice Parachute Jumpers

Abstract It was investigated whether a stress-induced analgesia could be demonstrated in human subjects (N = 24) performing a first-time parachute jump. Sensitivity for electrical stimulation and pressure pain was measured at several moments before and after the jump. The opioid antagonist naloxone or saline placebo was administered immediately after the jump to examine possible opioid-mediated effects. After the jump, the placebo group showed a lower pain sensitivity than the naloxone group, with the latter returning to pretest levels, consistent with an opioid-mediated analgesia. Although analgesic effects appear to have been initiated prior to the jump, plasma β-endorphin showed a sudden large increase immediately after the jump. This increase correlated with reports of anxiety and loss of control during the jump, and was associated with reduced pain sensitivity. Despite several limitations, this study suggests that the real-life stress of a parachute jump may attenuate pain through endogenous opioid release.

Risk as feelings

Virtually all current theories of choice under risk or uncertainty are cognitive and consequentialist. They assume that people assess the desirability and likelihood of possible outcomes of choice alternatives and integrate this information through some type of expectation-based calculus to arrive at a decision. The authors propose an alternative theoretical perspective, the risk-as-feelings hypothesis, that highlights the role of affect experienced at the moment of decision making. Drawing on research from clinical, physiological, and other subfields of psychology, they show that emotional reactions to risky situations often diverge from cognitive assessments of those risks. When such divergence occurs, emotional reactions often drive behavior. The risk-as-feelings hypothesis is shown to explain a wide range of phenomena that have resisted interpretation in cognitive-consequentialist terms.

Using minute ventilation for ambulatory estimation of additional heart rate

Both physical activity and emotion produce physiological activation. The emotional component of heart rate (HR) can be estimated as the additional HR (aHR) above that predicted by O2 consumption. Our innovation was to substitute minute ventilation (V) for O2 consumption, calculating aHR from individual relations between V and HR during an exercise test. We physiologically monitored 28 flight phobics and 15 non-anxious controls while walking (leaving the hospital, entering a plane), and during a commercial flight. Raw HR did not differ between phobics and controls when leaving the hospital (118/114 bpm) or entering the plane (117/110 bpm). However, although aHR was not different when leaving the hospital (7.0/8.6 bpm), it was significantly greater when entering the plane (17.5/9.9 bpm), accurately reflecting the increased subjective anxiety of the phobics. V was not higher in phobics than controls during any condition, suggesting an absence of hyperventilation in the phobics. The results demonstrate the utility of our method for analyzing HR in people whose stress occurs when they are physically active.