Memory impairment during a climbing traverse: implications for search and rescue climbing

Hyperbaric oxygen preconditioning rescues prolonged underwater exercise-induced hippocampal dysfunction by regulating microglia activation and polarization

Underwater exercise is becoming increasingly prevalent, during which brain function is necessary but is also at risk. However, no study has explored how prolonged exercise affect the brain in underwater environment. Previous studies have indicated that excessive exercise in common environment causes brain dysfunction but have failed to provide appropriate interventions. Numerous evidence has indicated the neuroprotective effect of hyperbaric oxygen preconditioning (HBO-PC). The objective of this study was to investigate the cognitive effect of prolonged underwater exercise (PUE) and to explore the potential neuroprotective effect of HBO-PC in underwater environment. Rats swimming for 3 h in a simulated hyperbaric chamber (2.0 ATA) was used to establish the PUE animal model and HBO-PC (2.5 ATA for 1, 3,5 times respectively) was administrated before PUE. The results demonstrated that PUE triggers anxiety-like behaviors, cognitive impairment accompanied by hippocampal dysfunction, microglia activation and neuroinflammation. Conversely, 3 HBO-PC rescued anxiety-like behaviors and cognitive impairment. Mechanistically, 3 HBO-PC reduced microglia activation and switched the activated microglia from a pro-inflammatory to neuroprotective phenotype. These findings illustrated that PUE induces anxiety-like behaviors and cognitive impairment and HBO-PC of proper frequency may provide an appropriate and less invasive intervention for protecting the brain in underwater exercise.

Mind over body: Interfering with the inner voice is detrimental to endurance performance

In two preregistered experiments, we investigated whether covert language is involved in sustained physical efforts, specifically if people are less able to push themselves physically when distracted from using inner speech. In both experiments, participants performed 12 cycling trials (Experiment 1: N = 49; Experiment 2: N = 50), each lasting 1 min where participants were required to cycle as fast as possible while simultaneously engaging in either a visuospatial task, a verbal task or no interference. Experiment 1: Participants performed worse in the verbal interference condition compared with the control condition (d = 0.29) and verbal interference performance was numerically but not significantly worse than visuospatial interference (d = 0.22). Experiment 2: A more demanding interference task yielded significant slower cycling with verbal interference compared to both control (d = 1) and visuospatial interference (d = 0.43). These results indicate that inner speech plays a causal role in control of sustained physical efforts.

Fear of falling in women: A psychological training intervention improves climbing performance

The main purpose of this study was to determine the effect of a psychological training intervention based on emotional regulation on anxiety and climbing ability in women climbers with fear of falling. A secondary aim was to compare the outcomes of climbing ability, anxiety, self-confidence and interoceptive awareness (IA) between the psychological group (PG), a training (TG) and a control group. Self-reported climbing ability, anxiety and IA were assessed using Competitive State Anxiety Inventory-2 and the Multidimensional Assessment of Interoceptive Awareness questionnaire. Results indicated a significant improvement in climbing ability for both PG and TG. The PG showed a significant reduction in cognitive and somatic anxiety, while the TG only exhibited a reduction in cognitive anxiety. Moreover, the PG demonstrated a greater significant increase in self-confidence compared to the TG. IA improved in five subscales for the PG, whereas the TG changed in only two subscales. In conclusion, a psychological training intervention focusing on emotional regulation might contribute to improvements in IA, reduced anxiety levels, and enhancements in climbing ability and self-confidence among women climbers facing fear of falling.

Dual-task effects between tone counting and mathematical calculations

We examined the impact of performing a tone counting task of varying cognitive loads and mathematical calculations simultaneously, compared to performance on the same tasks done individually. Participants performed continuous mathematical calculations, performed a high and a low cognitive load tone counting task, and also performed the math and counting tasks simultaneously. Performing the two tasks together resulted in significant dual-task interference. We also compared these results to previous studies employing the tone counting tasks with physically demanding tasks (climbing, kayaking and running). The interference between tone counting and mathematical calculations was worse than the interference between tone counting and running and kayaking. For climbing, the difference in interference was more nuanced with evidence indicating climbing uniquely asserts task prioritization. These findings have implications for operations requiring dual or multi-tasking.

The impact of cognitive load on kayaking and kayaking on cognitive performance

OBJECTIVE

We examined the impact of performing a cognitive task of varying loads and kayaking simultaneously, compared to performance on the same tasks individually.

BACKGROUND

When two tasks are performed together, performance often suffers compared to performance on either task alone. Interference not only occurs in competing cognitive tasks, but has also been found with certain physically demanding activities, such as climbing.

METHOD

Skilled kayakers performed a kayak course on open water, performed a high and a low cognitive load tone counting task, and also performed the kayak and counting tasks simultaneously.

RESULTS

Despite some past research finding dual task facilitation with laboratory aerobic activities, simultaneous kayaking and tone counting led to dual-task interference.

CONCLUSION

Concurrent counting and kayaking led to performance impairments in both tasks, relative to single task performance.

APPLICATION

The present results are applicable to occupations involving concurrent demanding physical activity and cognitive task performance, such as the work of first responders and military operators. PRéCIS: Kayaking, like climbing, appears to hinder cognitive performance more than the low-risk physical tasks carried out in laboratory conditions.

Dual-task interference while receiving information on a head mounted display and manual tracking with and without auditory warnings

BACKGROUND

Dual-task interference is a concern when users attempt to use head mounted displays (HMD) while performing seated manual control tasks. Auditory warnings of information displayed on the HMD may or may not assist users while multi-tasking.

OBJECTIVE

In this study, we investigated the dual-task interference of words, to be remembered later, presented on a HMD and motor control in a manual tracking task. The word presentations were warned or not warned with auditory signals and the impact of audio warnings were examined.

METHODS

Participants were required to perform five tasks: (1) a compensatory tracking task performed alone, (2) a word memory task performed alone, (3) a tracking and word memory task, (4) a word memory task with words preceded by audial signals, and (5) a tracking and word memory task with words preceded by audial signals. In addition, in the dual-tasks, half of the word presentations were paired with directions changes in the tracking task to test for immediate perceptual interference.

RESULTS

There were significant dual task costs for both mean tracking error and later word recall. Additionally, participants took significantly longer to respond to motion changes paired with word presentations than motion changes not paired with word presentations. However, the impact of auditory warnings on tracking performance was nuanced.

CONCLUSION

Even with an in field of view transparent HMD momentary and sustained cognitive dual-task interference remains. Reaction times are affected most in the worst case scenario, when task critical events occur at the same time as a text message.

APPLICATION

The use of HMDs in time critical manual control tasks (such as operating machinery) should be limited. The use of audial warnings to alert operators to information displayed on an HMD requires further research; it may disrupt appropriate or natural task ordering.

The impact of cognitive load on climbing and climbing on cognitive performance

OBJECTIVE

We examined the impact of increasing cognitive load on climbing performance and the impact of climbing on concurrent cognitive task performance.

BACKGROUND

Generally when two tasks are performed simultaneously performance of one or both suffers relative to performance of each alone. Such dual task decrement is not confined to competing cognitive tasks, but has also been found when one task involves demanding physical activity.

METHOD

Skilled climbers performed a traverse climb alone and in combination with low and high cognitive load counting tasks, which were also performed alone.

RESULTS

In more realistic physical settings, physical and cognitive tasks will interfere, unlike what some literature using laboratory physical tasks may indicate.

CONCLUSION

Compared to single task (climb only) performance concurrent counting and climbing resulted in impaired performance. However, climbers appeared to prioritize climbing over cognitive task performance.

APPLICATION

The results and this program of research have implications for occupations that involve concurrent demanding physical activity and cognitive task performance. PRéCIS: High risk, physical tasks in real world conditions appear to hinder cognitive performance more so than low-risk physical tasks carried out in laboratory conditions.

Physical Exercise Intensity During Submersion Selectively Affects Executive Functions

OBJECTIVE

The intact cognitive processing capacity in highly demanding and dynamically changing situations (e.g., in extreme environmental conditions) is of central relevance for personal safety. This study therefore investigated whether underwater physical exercise (PE) affected cognitive performance by comparing these effects during underwater fin-swimming as opposed to inactivity under normal environmental conditions.

BACKGROUND

Although acute bouts of PE can modulate cognitive performance under highly controlled and standardized laboratory conditions, no previous study has determined whether PE acutely modulates cognitive performance in non-laboratory testing conditions involving extreme environments (e.g., underwater).

METHOD

A total of 27 healthy volunteers (16 males and 11 females; 28.9 ± 7.4 years of age) participated in two experiments involving either moderate or high PE intensity. A PRE/POST crossover design was employed among participants while performing cognitive tests in a counterbalanced order (i.e., before and after 20 min of PE in submersion [WET] and once before and after inactivity [DRY] while in the laboratory). Cognitive performance was measured as a combination of executive functions through the Eriksen Flanker (inhibition) and Two-Back (working memory) Tasks using an underwater tablet computer.

RESULTS

ANOVAs revealed enhanced reaction times only in the Flanker test after moderate PE for the WET condition. No other effects were detected.

CONCLUSION

These findings indicate that cognitive performance is exercise-intensity-dependent with enhanced effects during moderate PE, even in extreme environments (i.e., underwater).

APPLICATION

These results should be relevant in recreational and occupational contexts involving underwater activity and may also apply to microgravity (e.g., during extra-vehicular activities).

DESCRIPTION

This study compared the acute effects of physical exercise (PE) on cognitive performance in an underwater environment while participants fin-swam with SCUBA (self-contained underwater breathing apparatus) gear. Findings revealed that 20 min of moderate PE positively affected cognitive performance (i.e., inhibitory control ability). However, no changes were observed after high-intensity exercise.

Dual-Task Interference Between Swimming and Verbal Memory

OBJECTIVE

A dual-task study was performed to explore the performance effects for swimming, word recall, and the combination of the two tasks performed simultaneously.

BACKGROUND

Dual-task interference studies have been performed for a variety of tasks; however, there has not been much dual-task interference research where one of the tasks is a naturalistic physically strenuous task. Swimming is a unique physical task that requires spatial orientation on three dimensional axes, similar to that of flying, but has no risk of falling. Previous studies have been conducted in other activity combinations with word-free recall, such as running and climbing, but swimming has yet to be explored.

METHOD

A verbal memory recall task and swimming task were performed in isolated (single-task) and simultaneous conditions. A comparison of effects across these different activities was also explored.

RESULTS

Swimming and the word-recall task resulted in significant dual-task interference: almost as much as when word recall was paired with another verbal task, but more than running and less than climbing.

CONCLUSION

Consistent with other dual-task studies, this study observed dual-task interference between the physical swimming task and the cognitive verbal memory task.

APPLICATION

Future technologies and training for personnel who engage in water rescue or commercial diving, such as underwater welding and fiber optic cable, may be improved by these findings.