Analysis of heart rate variability amongst cyclists under perceived variations of risk exposure

Cycling as a mode of travel provides an opportunity for many people to increase their levels of regular physical activity and contribute to their mental and physical health. Heart rate is often used as a means of measuring the intensity and energy expenditure of physical activity. However, heart rate is also linked to emotional factors such as anxiety and fear. Perceptions of risk due to external factors such as other road users and infrastructure may arouse such emotions in urban cyclists. The present study set out to investigate whether or not perceptions of risk among urban cyclists may lead to increased heart rates. Cyclists completed a test route in normal traffic conditions in Cork, Ireland and heart rates and self-reported risk ratings were recorded in real time. Evidence was found of a link between perceptions of risk and heart rates. This raises questions regarding the use of heart rate to estimate exercise intensity and energy expenditure during urban cycling. The perceptions of cyclists of their safety in relation to various road elements on familiar routes were also assessed, as well as specific events which they perceive to be high in risk. The results indicate that incidents involving car traffic and busy roads which offer no protection from interaction with car traffic are associated with greatest perceptions of risk.     

Cardiodynamic determinants of heart perception

Subjective perception of one's heartbeat is augmented by psychological factors (stress, fear) as well as by physiological influences (e.g., physical work). It is still unclear on which cardiac or circulatory parameters the "signal" for cardiac perception is based. In this study, the relation between cardiac performance and the ability to perceive one's heartbeat was investigated. Sixteen healthy subjects (8 female, 8 male, aged from 21 to 31 years) participated. Cardiac activity was varied by a combination of passive tilt and physical work on a bicycle ergometer. Subjects had to perform physical work (0, 25, 50, 75, 100 W) on the bicycle at seven different angles (90 degrees, 75 degrees, 60 degrees, 45 degrees, 30 degrees, 15 degrees, 0 degrees). A cardiac perception test was carried out after each load. The following cardiodynamic parameters were measured: stroke volume, contractility, and heart rate. The mean correlation coefficient between cardioceptive performance and cardiodynamic parameters was .62 for stroke volume, .45 for contractility, and .12 for heart rate. Obviously, a remarkable relation exists between the mass and--to a lesser degree--the velocity of ejected blood and cardiac perception. From this we infer, tentatively, that the subjectively perceivable heartbeat stimulus is generated by mechanical events that occur close to the left ventricle.     

The Effect of Fatigue on Learning and Performance of a Gross Motor Task

40 college males were sequentially assigned to 1 of 2 groups to examine the effects of induced physical fatigue upon the performance and learning of a gross motor task, the stabilometer. All Ss were given 32 practice trials over 3 practice sessions, with 48 hr. rest interpolated between sessions. Trials 1 and 2 were performed under control conditions (no fatigue) for both groups. The Experimental Group was then required to perform under conditions of physical fatigue during Trials 3-26. Trials 27-32 (Session 3) were performed under control conditions. The condition of fatigue was achieved on Trials 3-26 by having Ss pedal a bicycle ergometer until a heart rate of 180 beats/min was attained prior to each trial. The Control Group cancelled vowels. The results indicated that physical fatigue was detrimental to the performance and learning of the Experimental Group.     

Focused and fired up: Narrowed attention produces perceived proximity and increases goal-relevant action

Insufficient physical activity contributes to rising obesity rates. We tested one social cognitive strategy aimed at increasing physical activity in the environment. Specifically, we tested whether attentional narrowing can shift people’s perceptual representations of the environment and improve exercise behavior. Participants who adopted a narrow focus of attention, compared to participants who looked around the environment as they naturally would, perceived a target as physically closer (Studies 1, 2). In addition, narrowed attention reduced the time required to walk to a finish line and increased subjective ease of physical task performance, two markers of improved exercise (Study 2). We discuss implications of attentional strategies for perception and action in regards to health and fitness.     

Characteristics of older cyclists (65+) and factors associated with self-reported cycling accidents in the Netherlands

Cycling supports the mobility, health and independency of the ageing population. However, older cyclists have an increased injury risk. On average, the risk of older people to sustain an injury in a cycling accident is three times higher per cycling kilometre than for middle-aged people and the injury risk increases with age. In comparison with middle-aged cyclists (<65 years), the risk of hospitalization is more than four times as high for older cyclists (≥65 years). The aim of this study was to reveal characteristics of older cyclists in general and to explore which of these characteristics are associated with self-reported cycling accidents from age 59. More than eight hundred older cyclists (>65 years) filled out a questionnaire, which included questions on demographics, bicycle specifications and personal characteristics. By means of a logistic regression, the relationship between personal factors and self-reported bicycle falls were studied. The univariate models showed that age, physical and mental impairments, bicycle model, living environment, feelings of uncertainty of the cyclist and changed cycling behaviour (such as more patience, lower speed) were related to falling off a bicycle. From the multivariate model we can conclude that several factors are associated with falling off a bicycle in the older population: (1) every year the cyclists becomes one year older (from the age of 65), the chance they have fallen increases with 7.3%, (2) If cyclists have mental impairments, the chance they have fallen increases with a factor 2.5, (3) if cyclists were less than completely confident the chance they have fallen increases with factor 1.8, (4) if cyclists live in a rural environment compared to an urban environment the chance they have fallen increases with a factor 2.1. In conclusion, demographic, cycling and personal factors can be related to increased self-reported fall risk. It is advised to take these factors into account when implementing new cycling related safety measures.     

Varied intensities of training, predicted maximum oxygen uptake and the minimum threshold hypothesis

In this study, 24 sedentary first-year male university students aged 17 to 24 yr. were assigned to one of four groups. Three of the groups underwent a 6-wk. training program consisting of a 30-min. bicycle ergometer ride, three times per week. A fourth group acted as a control. The experimental groups trained at workload intensities corresponding to predetermined heart rates of 125, 140, and 155 bpm, respectively. Analysis of scores indicated that changes in aerobic capacity occurred only if the intensity of training exceeded a minimal level. Essentially, these results replicated data from other studies.     

EFFECTS OF A VARIABLE-RATIO REINFORCEMENT SCHEDULE WITH CHANGING CRITERIA ON EXERCISE IN OBESE AND NONOBESE BOYS

The effects of a variable-ratio schedule of reinforcement on pedaling a stationary exercise bicycle were examined. Three obese and three nonobese 11-year-old boys were individually tested five times weekly for approximately 12 weeks. A changing-criterion design was used in which each successive criterion was increased over mean performance rate in the previous phase by approximately 15%. The contingencies of the successive criteria resulted in systematic increases in rate of exercise for all children. Final variable-ratio rates were higher than those under fixed ratios found in previous research, with rates for 2 of the 3 obese boys approximating those of the nonobese.     

The Impact of Exercise on Hormones Is Related to Autonomic Reactivity to a Mental Task

This study examined the effects of an acute physical stressor on salivary testosterone (Tsal) and cortisol (Csal) and their relationship with the autonomic responsiveness to a mental task in fit young men (n = 30). Salivary testosterone (Tsal) and cortisol (Csal) levels were determined before and after a maximal bicycle exercise. Heart rate (HR) and skin conductance levels (SCL) were continuously recorded before, during, and after a Stroop task. Tsal and Csal levels diminished while HR and SCL increased in response to stressors in all the sample. When subjects were distributed in function of their endocrine response to the physical stressor, high Tsal responders showed higher HR reactivity than low responders, and high Csal responders showed higher SCL reactivity and lower reaction time in the Stroop task. These results show that the influence of an acute physical stressor on hormones is associated with the autonomic responses to a mental task.     

Effect of three levels of work intensity on performance of a fine motor skill.

The purpose of this study was to investigate the effect of three levels of work intensity on the performance of a fine motor skill during steady-state exercies. Subjects were administered a progressive bicycle ergometer test to exhaustion in order to determine maximum heart rate (HRmax). Following practice sessions on the pursuit rotor, subjects performed 3 different rides on a bicycle ergometer at 60, 75, and 90% of HRmax. The order to test administration was varied randomly in an attempt to control for sequential effects. Analysis of variance with repeated measures was used to determine differences in pursuit rotor performance by days and by levels of work intensity. No confounding of learning was noted. A significant F ratio (p less than .001) between work intensities showed that fine motor performance during steady-state exercise is affected by levels of work intensity.     

PRELIMINARY EVALUATION OF AN OBSERVATION SYSTEM FOR RECORDING PHYSICAL ACTIVITY IN CHILDREN

Although mechanical means of measuring physical activity are available, they cannot provide information about the context in which such activity occurs. Therefore, direct‐observation systems remain essential tools for studying physical activity. The Observational System for Recording Physical Activity in Children (OSRAC) is a direct‐observation system for recording physical activity and associated environmental variables. We evaluated the concurrent validity of the OSRAC physical activity codes with two types of mechanical measures of physical activity: pedometers and heart‐rate monitors. The results indicate that heart rates and step totals generally covaried with the OSRAC activity‐level codes, suggesting that these codes are valid measures of physical activity in preschool children. Copyright © 2011 John Wiley & Sons, Ltd.     

Be green and clearly be seen: How consumer values and attitudes affect adoption of bicycle sharing

Environmental concerns have propelled public and private entities to search for ways to increase usage of public bicycle sharing systems. However, usage rates in many cities remain below expectations. Using the theory of perceived value to motivate our hypotheses, this paper evaluates the impact of perceived value on consumer adoption intentions, and assesses the moderating effects of social and personal attitudes towards environmental behavior, on perceived value-adoption intention relationships. Our findings suggest that public bicycle sharing adoption intention is significantly influenced by its perceived functional, conditional, green and social values. Moreover, personal and social attitudes towards “greenness” and bicycle sharing, respectively, are found to moderate the relationship between perceived values and adoption intentions. This research contributes to theory-building in bicycle sharing adoption, and informs business and government leaders on how to promote adoption.     

Optimal pedaling rate in bicycle ergometer exercise determined by probe reaction time

The purpose of this study was to obtain the optimal pedaling rate in bicycle ergometer exercise by measuring probe reaction time, which is a good indicator of attention demand, by changing workloads and pedaling rates, and to discuss the relevant rhythm of lower limb movement. Subjects were 19 healthy men whose M age was 22.8 yr. They were instructed to pedal a bicycle ergometer, and their reaction time at different workloads and pedaling rates was measured to estimate an optimal pedaling rate. Probe reaction time was measured under the conditions as follows: pedaling rate of 20, 40, 60, 80, and 100 rpm at each workload of 40, 60, 80, 100, and 120 watts. The estimated values obtained by regression analysis for pedaling rate to give the minimum probe reaction time were 63.5 rpm for 40 watts, 58.8 rpm for 60 watts, 61.3 rpm for 80 watts, 63.4 rpm for 100 watts, and 64.8 rpm for 120 watts. These results indicated that the optimal pedaling rate was approximately 60 rpm regardless of the workload.     

Exercise-produced arousal, film-induced arousal and attribution of internal state.

Respiration rates were monitored on 20 high-anxious and 20 low-anxious female Ss while they were watching an anxiety-provoking film on industrial accidents. Half of the Ss exercised on a bicycle while half remained seated throughout their viewing of the film. Exercised Ss reported feeling less anxious while viewing the accidents compared with the inactive controls. All groups recalled similiar amounts of the film content, and respiration rates did not increase while viewing the accidents. Results of self-report of anxiety are consistent with a recently advanced theory of objective self-awareness.     

The effects of operating a touch screen smartphone and other common activities performed while bicycling on cycling behaviour

Although it has been shown that making phone calls or sending text messages while riding a bicycle can have a negative impact on bicyclist’s behaviour, in countries such as the Netherlands the operation of a mobile phone while cycling on a bicycle is not illegal and is actually quite common. In recent years conventional mobile phones with a physical keypad are increasingly being replaced by smartphones with a touch screen. The operation of a touch screen phone ironically cannot be done purely ‘by touch’ due to the lack of tactile feedback, and instead requires fixations on a relatively small screen. The question therefore can be asked whether the operation of touch screen telephones deteriorates cycling behaviour more than operation of a conventional mobile phone.Twenty-four participants completed a track on their own bicycle while sending a text message from a conventional and a touch screen mobile phone. In addition the effects of other common activities that can accompany bicycling were studied, including texting at the same time as listening to music, talking on a mobile phone or cycling next to someone and speaking with this companion, and playing a game on a touch screen phone while bicycling. The impacts of all the above conditions on cycling performance and visual detection performance were compared with control conditions in which participants cycled with either one or two hands on the handlebars and were not required to perform any secondary tasks.Bicycle speed was reduced in all telephone conditions and in the condition when cycling next to someone. Lateral position variation increased in all telephone conditions. Use of the touch screen led to a more central position in the cycle lane and resulted in worse visual detection performance compared with the operation of a conventional mobile phone. The main effect of listening to music was that an auditory signal to stop cycling was missed by 83% of the participants. In conclusion, while all investigated types of phone deteriorated cycling performance, the use of a touch phone has a larger negative effect on cycling performance than a conventional mobile phone. With touch screen smartphones taking the place of conventional mobile phones and being used for other purposes than verbal communication, these effects on cycling performance pose a threat to traffic safety.     

Cycling strategies of young and older cyclists

This study concentrates on the cycling strategies of older cyclists (54–62 year olds) in comparison to young cyclists (20–30 year olds). While cycling in a safe laboratory set-up, controlled lateral perturbations are applied to the rear of the bicycle. Three possible strategies to keep balance are analysed for a young and older aged group: steering, lateral trunk movement and outward knee movement. Older subjects appear to rely more on knee movement as a control mechanism than young subjects. Furthermore, the frequency domain analysis revealed that the older adults need more effort to counteract high frequency perturbations. Increased inter-individual variation for the older adults subject group suggests that this group can be seen as a transition group in terms of physical fitness. This explains their increased risk in single-sided bicycle accidents (i.e. accidents involving the cyclist only). Therefore, older cyclists could benefit from improving the stability of cycling at lower speeds.     

CHANGES IN BLOOD PRESSURE AND HEART RATE DURING FIXED‐INTERVAL RESPONDING IN SQUIRREL MONKEYS

Episodic and sustained increases in heart rate and mean arterial blood pressure can occur with recurring patterns of schedule‐controlled behavior. Most previous studies were conducted under fixed‐ratio schedules, which maintained a consistent high rate of responding that alternated with periods of no responding during times when the schedule was not in operation. The present study examined changes in heart rate and blood pressure under fixed‐interval schedules which maintained a range of rates that varied from little or no responding at the beginning of the fixed interval to high rates at the end of the interval. The relations of cardiovascular function to rate of responding were examined. Squirrel monkeys prepared with arterial catheters were trained to respond under fixed‐interval schedules of electric‐shock presentation. The duration of the interval was varied across sessions and cardiovascular parameters were examined. Local rates of responding were typically near zero during timeout periods, low at the beginning of each fixed‐interval cycle, and then increased as the fixed interval progressed. At most schedule durations, arterial blood pressure and heart rate levels were lowest at the beginning of the interval cycles, increased as the rate of responding increased, and then decreased during the timeout periods. At all parameters studied, there was a direct relationship between changes in response rate within fixed‐interval cycles and changes in heart rate and blood pressure. The results suggest that a much closer concordance of these cardiovascular parameters and schedule‐controlled responding is obtained by examining ongoing behavior as it occurs within the contingencies by which it is maintained.     

The rate of sedentary activities determines the reinforcing value of physical activity.

In this study, the authors examined whether the reinforcing efficacy of sedentary behaviors was related to their base rates. Base rates of 3 sedentary and 1 physical activity were determined for 40 sedentary adults. Participants were randomized to groups in which either high-rate, moderate-rate, low-rate, or no sedentary activity was contingent on being physically active. Noncontingent sedentary activities remained freely available. Contingent high- or moderate-rate sedentary activities increased physical activity, whereas no increases in physical activity were observed for contingent low-rate or control conditions. Thus, sedentary behaviors can be used to reinforce physical activity, their reinforcing efficacy depends in part on their base rates, and they are not completely substitutable.     

The heart beat does not make us tick: The impacts of heart rate and arousal on time perception

According to popular models of human time perception, variations in prospective timing are caused by two factors: the pulse rate of an internal pacemaker and the amount of attention directed to the passage of time. The results concerning the effect of attention on subjective timing have been conclusive, but the mechanisms that drive the pacemaker are still far from being understood. In two experiments, we examined the impact of two factors that in the existing literature on human time perception have been argued to affect such a pacemaker: arousal and heart rate. Experienced arousal and heart rate were varied independently by means of specific physical exercises: (a) A muscle exercise increased arousal and heart rate; (b) a breath-holding exercise increased arousal but decreased heart rate; and (c) in the control condition, arousal and heart rate were held constant. The results indicate that increased subjective arousal leads to higher time estimates, whereas heart rate itself has no relevant impact on time perception. The results are discussed with respect to the underlying mechanisms of prospective time perception.     

身体攻击行为学生自主神经活动的情绪唤醒特点

运用情绪生理学的方法,以31名具有身体攻击行为的初中工读学生和30名普通初中生为研究对象,研究了身体攻击行为学生与普通学生在基线生理唤醒和情绪生理唤醒的方面不同特点。结果发现,在生理唤醒的基线水平上,身体攻击行为学生与普通学生在指温、R-R间期、心率、指脉率方面差异显著,身体攻击行为学生的指温、心率、指脉率比普通学生低,身体攻击行为学生的R-R间期比普通学生R-R间期长。在愤怒刺激条件下,身体攻击行为学生报告的愤怒体验水平比普通学生高;愤怒诱发刺激引起身体攻击行为学生R-R间期、心率变化显著,而普通学生R-R间期、心率变化不显著。厌恶与恐惧、悲伤、愉快诱发刺激引起普通学生皮肤电变化显著,而身体攻击行为学生皮肤电变化不显著     

Vulnerability Beliefs, Symptom Experiences, and the Processing of Health Threat Information: A Self-Regulatory Perspective

This study used a self-regulation model of health behavior to explore the impact of risk perceptions and disease-risk symptoms on responses to health messages. Undergraduates with beliefs of high or low vulnerability to heart disease participated in a task that either did or did not induce disease-risk symptoms. Participants were then given a threatening or reassuring message about heart disease prevention, or no message. Participants with high-vulnerability beliefs reported higher exercise intentions only after the reassuring message, and then only in the absence of risk symptoms. However, their exercise rates were increased by both messages and by the symptoms. Participants with preexisting beliefs of low vulnerability reported higher risk perceptions after experiencing the symptoms; only the threat message enhanced their exercise rates.