Connect with us

Wellness

To ice or not to ice? Icing promotes muscle regeneration after mild injury

Cumulative research by a multi-institutional Japanese research collaboration reveals that ‘to ice or not to ice’ may depend on the degree of muscle injury.

Published

on

Applying ice to a muscle injury is a widespread first-aid treatment, but exactly what effect does this have on the muscle regeneration and does it really help? Cumulative research by a multi-institutional Japanese research collaboration reveals that ‘to ice or not to ice’ may depend on the degree of muscle injury.

In their latest research, the group consisting of Associate Professor ARAKAWA Takamitsu and Master’s student NAGATA Itsuki (from Kobe University’s Graduate School of Health Sciences), and Assistant Professor KAWASHIMA Masato (Kawasaki University of Medical Welfare) et al. have shown that applying ice to muscle damage in a small percentage of muscle fibers in rats promotes muscle regeneration. This is believed to be the first study in the world to show benefits of icing on muscle repair. In conjunction with their previous study on serious muscle injuries (‘Icing muscle injuries may delay recovery’), it is hoped that these results can be used as a basis for more accurate guidelines on whether or not to ice such injuries.

These research findings were first reported in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology on March 6, 2023.

Main Points

  • The experiments showed that applying ice after a mild muscle injury promotes muscle regeneration.
  • This is believed to be the first time in the world that a study has shown a positive effect of icing on muscle regeneration.
  • The researchers showed that the extent of the injury may have a greater impact on the effectiveness of icing than the method or timing employed.
  • The findings of this ongoing research will lead to the spread of more accurate information on the effects of icing throughout hospitals, and in the realms of sports and physical education.

‘RICE treatment’ is a common approach for treating the acute phase of sports injuries. This acronym stands for Rest, Ice, Compression and Elevation and it is also often used in physical education in schools and even clinical settings. There are a variety of subsequent steps that can be taken to treat the injury afterwards, yet opinions vary as to whether or not icing should be applied. However, there is a lack of evidence on the benefits of icing.

The current research team has conducted many experiments to investigate the effectiveness of icing, which led them to publish their previous findings (‘Icing muscle injuries may delay recovery’ ). However, no previous animal experiments have indicated that icing promotes muscle regeneration.

In this study, the researchers focused on altering the severity of the muscle injury in the experiments. The reasoning behind this was that the majority of sports-related muscle injuries are limited; in other words less than 10% of the overall number of muscle fibers (myofibers) are damaged and necrotized. However, all animal experiments up until now had looked at more serious injuries where over 20% of the myofibers were damaged.

Thus, the team devised an animal model for mild muscle injuries, and experimented with applying ice after injury using a similar method as before.

After the animal was anaesthetized, the muscle was exposed and clamped between forceps to induce injury. In their previous experiments, the researchers attached a 500g weight to the forceps, which induced an injury that affected 20% of the total number of fibers in the muscle. In the present study, they tried attaching a 250g weight to the forceps and demonstrated that this could be used to consistently injure 4% of the fibers (Figure 1). This is similar to the degree of injury that often occurs after sports activities such as vigorous exercise or long-distance marathon running.

Icing was carried out by placing polyethylene bags of ice on surface of the skin over three 30-minute sessions per day, with each session being 1.5 hours apart. This was continued until two days after injury for a total of 9 icing sessions (i.e. immediately after injury = 3 sessions, 1 day after injury = 3 sessions, 2 days after injury = 3 sessions). The icing method was the same as in the previously reported study (‘Icing muscle injuries may delay recovery’).

Observations of muscles that were regenerating in the icing group and no-icing group 2 weeks after injury revealed significant differences in the size of regenerating fibers in cross-sections (Figure 2). In other words, this demonstrated the possibility that skeletal muscle regeneration is promoted by icing.

Macrophages are immune cells that orchestrate the reparative process of injured muscle. Pro-inflammatory macrophages accumulate in the damaged site soon after injury occurs, however they express an inducible nitric oxide synthase (iNOS), which has a disadvantageous side-effect of expanding the injury’s sizeThe results of this team’s experiments revealed that icing after mild muscle injury reduces the accumulation of iNOS-expressing pro-inflammatory macrophagesBy causing this phenomenon, icing prevents the expansion of muscle injury size.

In other words, icing attenuates the recruitment of pro-inflammatory macrophages in the injury site. This was also reported in their previous study (‘Icing muscle injuries may delay recovery’), demonstrating that this is an effect caused by icing regardless of whether the muscle injury is serious or mild. In the previous study, icing was found to delay the regeneration of muscle after a serious injury that destroyed many fibers because the pro-inflammatory macrophages were unable to sufficiently phagocytose (*5) the injured muscle. In contrast to this, the current study shows that icing has a positive effect when the muscle injury is mild because it prevents the secondary expansion of the muscle injury caused by the pro-inflammatory macrophages. It suggests that this particular effect of icing is connected to the promotion of muscle regeneration.

Icing has been used in the treatment of muscle injuries for a long time, however the positive effects of icing had yet to be elucidated until now. This study has shown that icing can promote muscle regeneration when used to treat commonly-occurring mild muscle injuries.

However, this does not mean that icing is effective for all types or degree of muscle injury. The researchers aim to further elucidate and raise awareness of this. For example, the group’s previous study showed that icing actually inhibited regeneration in cases of serious muscle injury. In addition, the term ‘muscle injury’ also includes extremely minute injuries that have yet to be observed through the team’s animal experiments, so it is still unclear as to what effect icing has on the repair from such microtraumas.

The researchers’ next challenge is to determine the extent of muscle injury up to which icing is appropriate. By building upon their previous investigations, they aim to contribute towards guidelines that will enable people in sports and clinical rehabilitation to make accurate judgements about whether or not to ice an injury.

Zest Magazine accepts contributions promoting everything about living the good life (and how to make this so). C'mon, give us a yell.

Wellness

Aerobic exercise performed in the evening benefits elderly hypertensives more than morning exercise

Evening training was more effective in terms of improving cardiovascular autonomic regulation and lowering blood pressure. This can be partly explained as due to an improvement in baroreflex sensitivity and a reduction of muscle sympathetic nerve activity, which increased in the evening.

Published

on

Aerobic training is known to regulate blood pressure more effectively when practiced in the evening than in the morning. Now, researchers conducted a study of elderly patients at the University of São Paulo’s School of Physical Education and Sports (EEFE-USP) in Brazil, and they concluded that evening exercise is better for blood pressure regulation thanks to improved cardiovascular control by the autonomic nervous system via a mechanism known as baroreflex sensitivity.

An article on this study, “Evening but not morning aerobic training improves sympathetic activity and baroreflex sensitivity in elderly patients with treated hypertension”, was published in the The Journal of Physiology.

“There are multiple mechanisms to regulate blood pressure, and although morning training was beneficial, only evening training improved short-term control of blood pressure by enhancing baroreflex sensitivity. This is important because baroreflex control has a positive effect on blood pressure regulation, and there aren’t any medications to modulate the mechanism,” Leandro Campos de Brito, first author of the article, said.

In the study, 23 elderly patients diagnosed and treated for hypertension were randomly allocated into two groups: morning training and evening training. Both groups trained for ten weeks on a stationary bicycle at moderate intensity, with three 45-minute sessions per week.

Key cardiovascular parameters were analyzed, such as systolic and diastolic blood pressure, and heart rate after ten minutes’ rest. The data was collected before and at least three days after the volunteers completed the ten weeks of training. 

The researchers also monitored mechanisms pertaining to the autonomic nervous system (which controls breathing, heart rate, blood pressure, digestion, and other involuntary bodily functions), such as muscle sympathetic nerve activity (which regulates peripheral blood flow via contraction and relaxation of blood vessels in muscle tissue) and sympathetic baroreflex sensitivity (assessing control of blood pressure via alterations to muscle sympathetic nerve activity).

In the evening training group, all four parameters analyzed were found to improve: systolic and diastolic blood pressure, sympathetic baroreflex sensitivity, and muscle sympathetic nerve activity. In the morning training group, no improvements were detected in muscle sympathetic nerve activity, systolic blood pressure or sympathetic baroreflex sensitivity.

Evening training was more effective in terms of improving cardiovascular autonomic regulation and lowering blood pressure. This can be partly explained as due to an improvement in baroreflex sensitivity and a reduction of muscle sympathetic nerve activity, which increased in the evening.

“For now, all we know is that baroreflex control is the decisive factor, from the cardiovascular standpoint at least, to make evening training more beneficial than morning training, since it induces the other benefits analyzed. However, much remains to be done in this regard in order to obtain a better understanding of the mechanisms involved,” said Brito.

Baroreflex sensitivity regulates each heartbeat interval and controls autonomic activity throughout the organism.

“It’s a mechanism that involves sensitive fibers and deformations in the walls of arteries in specific places, such as the aortic arch and carotid body. When blood pressure falls, this region warns the brain region that controls the autonomic nervous system, which in turn signals the heart to beat faster and tells the arteries to contract more strongly. If blood pressure rises, it warns the heart to beat more slowly and tells the arteries to contract less. In other words, it modulates arterial pressure beat by beat,” Brito said. 

In previous studies, the EEFE-USP research group showed that evening aerobic training reduced blood pressure more effectively than morning training in hypertensive men (read more at agencia.fapesp.br/34194), and that the more effective response to evening training in terms of blood pressure control was accompanied by a greater reduction in systemic vascular resistance and systolic pressure variability (read more at agencia.fapesp.br/37432).  

“Replication of the results obtained in previous studies and in different groups of hypertensive patients, associated with the use of more precise techniques to evaluate the main outcomes, has strengthened our conclusion that aerobic exercise performed in the evening is more beneficial to the autonomic nervous system in patients with hypertension. This can be especially important for those with resistance to treatment with medication,” Brito ended.

Continue Reading

Wellness

Heart failure patients who do yoga have stronger hearts, can be more active

Patients who did yoga had healthier hearts and were more able to carry out ordinary activities such as walking and climbing stairs than those who only took medications. Patients with heart failure should speak to their doctor before starting yoga and should then receive training from an experienced instructor.

Published

on

Yoga focused on breathing, meditation, and relaxation is linked with symptom improvement in patients with heart failure.

This is according to research presented at Heart Failure 2024, a scientific congress of the European Society of Cardiology, with the study’s author, Dr. Ajit Singh of the Indian Council of Medical Research (ICMR), Manipal Academy of Higher Education, India, emphasizing that “patients who practiced yoga on top of taking their medications felt better, were able to do more, and had stronger hearts than those who only took drugs for their heart failure. The findings suggest that yoga can be a beneficial complementary therapy in patients with heart failure.”

Heart failure affects vast numbers of people – more than 64 million globally – and can have devastating impacts on quality of life, with patients feeling tired and breathless, and being unable to participate in their usual activities. While previous studies have shown the short-term benefits of yoga in patients with heart failure.

This study enrolled patients aged 30 to 70 years with heart failure from the cardiology outpatient department of Kasturba Hospital in Manipal, India. All participants had undergone a cardiac procedure within the past six months to one year and were taking guideline-recommended heart failure medications. Patients with severe symptoms were excluded.

The study included 85 patients. The average age was 49 years and 70 (82%) were men. In a non-randomised fashion, 40 patients were assigned to the yoga group and 45 patients were allocated to the control group. All participants continued taking guideline-recommended heart failure medications throughout the study.

Experienced faculty in the hospital’s Department of Yoga demonstrated pranayama (yogic breathwork), meditation, and relaxation techniques to patients in the yoga group. Participants were supervised for one week and then advised to continue self-administered yoga at home once a week for 50 minutes. Patients spoke to an instructor after each home session to check progress.

At baseline, six months, and one year, the researchers assessed heart structure and function in the yoga and control groups using echocardiography. The measurements included the ability of the heart to pump blood (left ventricular ejection fraction), and assessment of right ventricular function. The researchers also examined blood pressure, heart rate, body weight, and body mass index. Symptom burden and the ability to do ordinary activities such as walking and climbing stairs were assessed using the New York Heart Association classification system.

Compared to the control group, the yoga group demonstrated significantly greater improvements in all measurements at six months and one year relative to baseline.

Dr. Singh said: “Patients who did yoga had healthier hearts and were more able to carry out ordinary activities such as walking and climbing stairs than those who only took medications. Patients with heart failure should speak to their doctor before starting yoga and should then receive training from an experienced instructor. Prescribed medications should be continued as before. Yoga may be unsuitable for heart failure patients with severe symptoms, who were excluded from our study.”

Continue Reading

Wellness

Running under a four-minute mile could be the key to a long and healthy life

Elite runners live on average almost five years longer than the general population.

Published

on

The more – and faster – you run, the better for your health?

A study released to mark the 70th anniversary of Sir Roger Bannister’s sub-four-minute mile record revealed the first 200 runners to follow in his footsteps also share another remarkable trait. More particularly: the study from investigators in Australia and Canada found the 200 elite runners live on average almost five years longer than the general population.

The study, published in the British Journal of Sports Medicine, demonstrate the vital importance of aerobic fitness.

According to Professor Mark Haykowsky: “Breaking the four-minute mile was an extraordinary achievement 70 years ago and revealed just what the human body can achieve. It set off a wave of runners following in Sir Roger’s mighty footsteps.

“Remarkably we found that like Sir Roger, who lived to the ripe old age of 88, most of the first runners also lived well into their 70s, 80s and a majority are alive and healthy today.”

The multi-national team tracked down the health records of the first 200 people to complete the sub-four-minute mile. This included runners from the UK, Australia, France, New Zealand, and the United States who were born between 1928 to 1955. All 200 runners are men, and a majority were still alive.

Professor Andre La Gerche, a sports cardiologist who heads the HEART Laboratory supported by St Vincent’s Institute of Medical Research and the Victor Chang Cardiac Research Institute in Australia, says: “Our study set out to see how exercise affected elite athletes over the long term. We know that elite athletes have bigger hearts due to their sustained aerobic output and there was some belief that this could affect their health and longevity, but we found the opposite.

“Five years of extra life compared to average is very significant, especially when we found that many of these runners not only enjoyed long lives but were also healthy too.

“Not everyone needs to be able to run a sub-four-minute mile to enjoy good health long into old age, but they need to exercise regularly and push themselves aerobically.”

The world record for the mile now stands at 3.43 and is held by Hicham El Guerrouj of Morocco. Ollie Hoare is the fastest Australian (3.47.48) and Kevin Sullivan holds the Canadian record (3.50.26) both of which were set at the Bislett Games in Oslo, Norway. No female runner has yet broken the four-minute barrier. The women’s world record is currently at 4:07.64, set by Faith Kipyegon of Kenya in 2023.

Continue Reading
Advertisement
Advertisement

Like Us On Facebook

Facebook Pagelike Widget

Most Popular

Copyright ©FRINGE PUBLISHING. All rights reserved.