New Study Does Not Recommend Standing Desks

Picture from CMD

I have written previously on the ill effects of sitting and prolonged sitting. This has also led to the phrase that "sitting is the new smoking". Which subsequently led to standing desks as a 'trendy' option to offer a way to reduce sitting time.

Previously, some of my patients have also asked me to write a memo for them so they can get  their company to pay for a standing desk at work, while other patients have simply asked for my opinion.

My take on standing desks then? I've seen many of my patients go straight from sitting to a standing desk get different problems. Being unaccustomed on their feet all day long posed new risks. It can inhibit proper circulation and add additional pressure to your legs, hips and lower back. Sort of like jumping from the frying pan into the fire if you ask me.

My suggestions for these patients was not to switch to a standing desk for the full work day, especially if they have been sitting all day immediately. To make sure they gradually phase it in.

Like previous ergonomic chairs, desks etc, there hasn't been much evidence supporting the benefits of standing desks. The earlier limited studies did not comprehensively assess long term health consequences.

In a newly published study this month (Ahmadi et al, 2024), 83, 013 participants wore devices for up to 7 years to track their sitting, standing and physical activities. This was more accurate and objective than self reporting by subjects. The researchers found that sitting for more than 10 hours a day was associated with a higher risk of heart disease and stroke.

The researchers also found that standing more did not mitigate this risk of stroke and heart disease. In fact standing for extended periods was linked to a increased risk of circulatory problems. This suggested that simply changing from stationary sitting to standing will not solve the problem since our bodies respond better to movement rather than staying in static positions. Remember motion is lotion.

Workplace interventions that promote movement found that office workers who reduce sitting time by adding light walking and standing had improvements in blood sugar levels.

So, walk to your colleague to talk to them instead of calling or emailing, take the stairs often instead of elevators, walking to the pantry etc all contribute. Better still if you can do 10 bodyweight squats every 45 minutes. All these can make a significant difference.

Reference

Ahmadi MN, Coenen P, Straker L et al (2024). Device-measured Stationary Behaviour And Cardiovascular And Orthostatic Circulatory Disease Incidence.  Int J Epidemiol. 53(60: dyae136. DOI: 10.1093/ije/dyae136

*Note that the study's large population use and the use of devices to measure objective data strengthen the findings. However, observational studies may not totally establish cause and effect. Also since the average age of the subjects was about 61 years, it may not totally apply to younger popuplations.

Single Leg Versus Double Leg Training

L leg bigger

We see many cases where patients have one limb bigger than the other in our clinics. There is an imbalance or deficit between limbs e.g. healthy versus injured, left versus right or dominant versus non dominant. This is also known as interlimb asymmetry in research. 

Strength, power, reactive strength have been shown to be affected when there were interlimb asymetries, especially in sporting performances. I have seen differences of 10-15 percent in deficits for patients even 5 years after they had surgery. Hence, I often suggest that patients work on single limb exercises to reduce this deficit/ asymmetry.

Single leg and double leg strength exercises, plyometrics, balance and even core training have been investigated in a wide variety of athletic populations to understand the effects of interlimb asymmetry. The following systematic analysis was to examine if training interventions are effective in reducing interlimb asymmetries and which types of interventions were more effective in the athletic population.

The single leg counter movement jump (SLCMJ), single leg broad jump (SLBJ), single leg lateral jump (SLLJ) and change of direction (COD) speed were the most commonly used test to check for sprint performance, jump height and COD speed.

Ready for the results? The review suggested that all training interventions have a small to moderate effects on the reduction of asymetry in SLBJ, SLCMJ and COD speed from pre to post training, although no statistically significant differences were reported. This was found in the intervention groups versus the control groups.      

The researchers suggested both unilateral and bilateral training should be considered to decrease interlimb asymmetries. If you're an athlete and have any limb asymmetries and no pain, then definitely do both single and double leg exercises to reduce the asymmetry. 

Please note that the above study was done on athletic populations. I will definitely avoid single leg exercises in the recently injured/ immediate post surgery patients and get them to do bilateral leg exercises first.

What about patients who are not loading equally a year (or longer) after a knee replacement or ACL reconstruction? I always see patients who tend to compensate too much with the non injured/ painful leg. By doing single leg exercises (pictured above), I can make their weaker side work harder.

Reference

Bettariga F,Turner A, Maloney S et al (2021). The Effects Of Training Interventions On Interlimb Asymmetries: A Systematic Review With Meta-Analysis. Strength Cond J. DOI: 10.1519/SSC.0000000000000701

Your Workout Today May Trigger A bright Idea Next Week

Picture from Triana et al (2024)

What if I told you your exercise session today can trigger a bright idea next week? That's exactly what a recent study by Finnish researchers found. They tracked a person's brain and behavioural activity for 5 months using brain scans and data from smart phones and wearable devices. 

This research (Trinan et al, 2024) was unusual since few brain scan studies involve such detailed monitoring over months. Using wearable technology in this study was crucial, especially since brain scans (while being useful) only shows the subject lying still for 30 minutes. 

2 distinct patterns were identified by the researchers. A short term wave that lasted under 7 days and a long term wave by up to 15 days. The short term wave reflects rapid adaptations like how focus is affected by poor sleep although it recovers quickly. The long term wave suggests more gradual, lasting effects, especially in areas tied to our attention and memory.

The study found that our brains do not respond to our activities of daily living in immediate, isolated bursts. Our brain activity evolves in response to our sleep patterns, physical activity, mood, and respiration rate over many days. This means that your exercise session or a restless night from the previous week can still affect your brain. Hence your memory, cognition and attention can be affected well into the next week.

It is a great study linking brain activity with environmental and physiological data as tracking our brain changes in real time can help detect mental health and neurological disorders early. This allows for earlier interventions and better outcomes.

Even though this study was not focused exclusively on exercise, the results showed that we definitely need a consistent exercise routine and maintain good sleep habits for our overall well being. I find myself particularly sensitive to these as I age. 

Reference

Triana AM, Salmi J, Hayward NME et al (2024). Longitudinal Single-subject Neuroimaging Study Reveals Effects Of Daily Environmental, Physiological, And Lifestyle Factors On Functional Brain Connectivity. Plos Bio. DOI: 10.1371/journal.pbio.3002797

Something You Do Not Know About Muscles

Picture from Burke et al, 2024

This is a very interesting finding about muscles. The muscles we use while exercising can actually communicate with our adipose (fat) stores in our body.

This study was done with 32 human subjects. A single bout of resistance exercise (or strength training) releases muscle specific microRNA-1 (miR-1) from muscles that are then transported to abdominal fat tissue via extracellular vesicles or EVs to stimulate lipolysis. Lipolysis is the breakdown of fats and other lipids to release fatty acids. This means you can use fats for energy, sparing your carbohydrate and protein.

I know what some of you reading must be thinking. Is spot reduction possible? Spot reduction means selective loss of body fat in regions involved in the exercise. Meaning can we isolate the fat in the abdomen (for men) by doing cruches or sit-ups?  Or doing lunges for the buttock and thighs (for women) and get rid of the fat there first? 

Well, sorry to disappoint you. In this study, the exercises were mainly done in the lower body- squats, leg press, leg extension and also lat pulldown (for the upper body). 3 sets of 8 reps at 80 percent of 1 rep max on the aboved mentioned exercises were performed. A fourth set to failure was performed straight after.

The lipolysis or fat breakdown in the adipose tissue was in a non specific area - the abdominal region. This was confirmed by the EV's found there.

Perhaps this is an interesting consideration suggesting that our muscles can function like a secretory organ. Like a giant endocrine organ in the body, more than we realize anyway. (Note : thoughts are my own, not from the study).

We are definitely only scratching the surface of understanding how exercise has so many other unknown benefits.

The women in the study did not have as strong an effect compared to the men in the study. Also note that is is a relatively small study with only 32 subjects.

If you are not already doing any strength training, you should. Not only it can increase your bone density, helps with insulin sensitivity, promote better sleep etc, it can also break down your stored fat.

Reference

Burke BI, Ismaeel A, Long DE et al (2024). Extracellular Vesicle Transfer Of miR-1 To Adipose Tissue Modifys Lipolythic Pathways Following Resistance Exercise. JCI Insight. DOI: 10.1172/jci.insight.182589

Best Grip For Strength Training

Pronated (overhand) grip

My son and I were discussing what grips work best while performing strength training exercises that require us to hold weights when we push, pull or carry. Especially also when doing pull-ups. He was really surprised that such a small detail like the orientation of his grip can have dramatic increase in weight lifted or reps done.

The pronated (or overhand grip) is probably the most commonly used when you do a pull-up or do a strict deadlift. While a supinated (or underhand) grip is used when you do a dumbbell curl or a chin-up. 

Alternate (mixed) grip

There is also the mixed (alternated) grip (pictured above) in which one hand is pronated and the other is supinated. A neutral grip is when both palms (or fists) face each other like when doing a hammer curl. A hook grip (pictured below)is often preferred by advanced lifters when using very heavy weights. The thumb is 'hooked' between the bar and wrapping your index and middle fingers around the thumb for a more secure hold.

Hooked grip

I explained to my son when it comes to grip positions, it is all about all about anatomy. Even slight variations in hand positions during a lift will change which muscles you are using. 

Let's look at the dumbbell curl. When you use the supinated grip, your biceps are the prime movers. When you rotate your hands 90 degrees to a neutral grip, the emphasis changes to a different elbow flexor, your brachialis. If you rotate your hands 90 degrres again to a pronated grip, you will target brachioradialis, yet another elbow flexor.

Supinated (underhand) grip

How do you choose between the supinated versus the pronated grip? It usually depends on the exercise. It will be difficult to do the standard deadlift with a supinated grip since it would be more difficult to hold the bar. Other than that, the main difference between the 2 grips will be the slight difference in muscle recuitment.

Similarly doing pull-ups with the pronated grip will target your latissimus dorsi and trapezius more while the supinated grip for chin-ups will involve your biceps more.

From previous experience,  a grip change is often useful for any exercise that you have not had a significant improvement in the last 4-6 weeks. Say you have not been able to increase weight in your bicep curl, try the hammer curl as it will target your brachialis, which is the strongest of the elbow flexors.

A word of caution, do not try to change your grip for the Olympic lifts (if you do them) since they already work best within the rules of the sport.

With other lifts, a small change can get bigger gains.

Still Doing Those Pendulum Exercises For Shoulder Pain?

Quite a few patients who came to our clinic this week had frozen shoulder. Almost all of these patients had been prescribed pendulum exercises (also know as Codman pendulum exercises) by their previous healthcare provider. The intention is to move/ rehabilitate the glenohumeral (or shoulder) joint while not worsening recently injured or operated tissue.

This is done with the patient standing with a slightly bent torso with the affected arm hanging downwards, using the momentum of the torso/ trunk to move the arm without activating the muscles in the shoulder girdle. The arm can be moved side to side, forwards and backwards, or in a circular motion. Codman pendulum exercises are also always  prescribed after shoulder surgery . In fact, they are the mainstay of many shoulder rehabilitation protocols.

However, Cunningham et al (2020) demonstrated that Codman pendulum exercises involved minmial glenohumeral and scapular-thoracic movement. Movement is mainly from the trunk. They may be a safe way to start early movement/ stretching of the upper limb but may be of limited further use in restoring passive shoulder range of motion.

In fact Gurney et al (2016) found that Codman pendulum exercises induced the least muscle contraction in rotator cuff activity when they investigated several tasks, common rehabilitation exercises and ambulation. Wearing and taking off a shirt induced the highest. Even walking produced substantially higher muscle activity than the Codman exercises. 

Of course if the movement is directly generated from the shoulder rather than the trunk as well as performing larger pendulum circles, there will be increased rotator cuff muscles activity.

Personally, in our clinic, I find that teaching patients 3 basic exercises with elastic resistance bands work much better for the shoulder. Intensity, dosage and exercise position will have to be modified dependent on the surgery and condition the patient has. 

I show them the one arm shoulder frontal raise (pictured above), the lateral raise and a simple basic rowing exercise where the shoulder blade is retracted (or pulled back). In fact, the same few exercises and the single arm reverse fly (pictured below) were found to be effective for office workers to perform daily for 10 minutes to reduce neck and shoulder pain (Saterbakken et al, 2020). 

From Saterbakken et al (2020)

You can definitely stop doing those Codman pendulum exercises.

References

Cunningham G, Charbonnier C, Ladermann A et al (2020). Shoulder Motion Analysis During Codman Pendulum Exercises. Arthrosc Sp Med Rehab. 2(4): e339. DOI: 10.1016/j.asmr.2020.04.013

Gurney AB, Mermier C, LaPlante M et al (2016). Shoulder Electromyography Measurements During Activities Of Daily Living And Routine Rehabilitation. Ex J Orthop Sp Phy Ther. 46(5): 375-383. DOI: 10.2519/jospt.2016.6090.

Saterbakken AH, Makrygiannia P, Stien N et al (2020). Dose-response Of Resistance Training For Neck-and Shoulder Pain Relief: A Workplace Intervention Study. BMC Sp Sci Med Rehab. 12:8. DOI: 10.1186/s13102-020-0158-0

When Does Your Body Age The Fastest?

Picture by Steven Gregor from The Guardian

I always thought that age was just a number. How you feel is more important. Definitely being young at heart helps too. Mentioned this to my friend who's in his 60's while cycling this morning and he said that's the problem when you are young at heart. He said that he feels young at heart but the problem is that his heart is not that young.

Newly published research from Stanford University suggest that humans age very quickly in 2 periods, once around age 44 and the other around 60 (Shen et al, 2024).

Researchers in this study collected and analyzed more than 135,000 biological samples from 108 subjects ranging from 25 to 75 years. Cytokines, skin, oral, nasal microbiome, proteins, lipids, bacteria, ribonucleic acid etc were studied. They found that at around 44 years, those studied had a dramatically different mix of molecules than others just a few years younger. This indicates a spike in the risk of a heart attack, faster skin and muscle aging and slower alcohol and caffeine metabolism.

The next period of acclerated aging happened around age 60. More signs of aging for the heart, skin and muscles. Once into the 7th decade, our immune systems are weakened, kidney function reduces and decreased carbohydrate metabolism that can lead to Type II diabetes.

This shows that biological aging is not linear. It depends on our lifestyles primarily and genetics secondarily and how they interact. For many people, the early 40's and 60's tend to align with major life changes. Your children leaving for university, stopping work, downsizing your home etc.These changes may influence your diet, exercise, social exposure and other factors that affect how your bodies work.

Can we slow the biological aging? The researchers suggest adopting healthy lifestyle habits and ditching the bad ones to delay the aging in the 40's and 60's. If you are not yet 40, start paying attention to heart healthy habits, monitoring especially your cholesterol and triglycerides levels. Have a healthy diet, get enough exercise, minimise smoking and sugar.

Research suggests calorie restriction may protect health and longevity by protecting DNA from age related changes. Subjects who ate less calories by an average of 12 percent slow down their rate of aging by 2-3 percent (Waziry et al, 2023).

Bad sleep does not only make you tired, but makes you look old and haggard. Sleeping less than 6 hours each night can add about 15 months to your biological age and speed up the pace of aging (Kusters et al, 2024). Make sure you get enough shut eye.

Steven Gregor from The Guardian

Those who are yet to hit their 60's definitely need to strength train since muscle loss accelerates. Losing 1 to 2 percent of your muscle mass every year causes you to lose your ability to move freely and easily. Your health plummets as a result. A recent study by Da Silva et al (2024) showed that middle aged and older adults who did 12 weeks of progressive strength training delayed or even reversed sarcopenia (age related muscle loss). 

Now you know.

References

Da Silva AC, Mapa V, Ferreira-Junior JB et al (2024). Progressive Strength Training Can Reverse Sarcopenia Stage In Middle-aged And Older Adults Regardless Of Their Genetic Profile. Arch Geron Geriatrics. Vol 117. DOI: 10.1016/j.archger.2023.105182

Kusters CDJ, Klopack ET, Crimmins EM et al (2024). Short Sleep And Insomnia Are Associated With Accelerated Epigenetic Age. Pysch Med. 86(5): p453-462. DOI: 10.1097/PSY.0000000000001243

Shen X, Wang C, Zhou X et al 92024). Nonlinear Dynamics Of Multi-omics Profiles During Human Aging. Nat Aging. DOI: 10.1038/s43587-024-00692-2

Waziry R, Ryan CP, Corcoran DL et al (2023). Effect Of Long-term Caloric Restriction On DNA Methylation Measures Of Biological Aging In Healthy Adults From The CALERIE Trial. Nat Aging. 3(6): p249-257. DOI: 10.1038/s4357-022-00357-y