That isn’t just panting. It’s an aging heart running low on energy.
The seven signs owners write off as “just old age,” and the one muscle that never gets a day off.
Dr. Mark Saraiva, DVMVeterinary consultant to Pawprint · Updated on 10/2026
The walk you cut short. The way he lowers himself onto the sidewalk and will not go on. At 2 a.m. you are the one lying awake, hand on his ribs, counting his breaths and listening to a cough you told yourself was nothing.
Maybe his vet “just mentioned” a murmur at the last checkup, and you have been carrying it ever since. “It’s just old age” is no longer an answer.
Below: the seven signs owners write off, what is really happening in the one muscle that has never taken a day off, and why nothing you have tried has been enough.
7 signs his heart is working harder than it should, the ones owners write off as “just old age”
Coughing, breathing that has gone fast or heavy, tiring on exercise, restlessness, fainting: these are the signs a heart in trouble gets named for [1][2]. Here is how they look in your home.
Walks that end earlyHe drags behind, slows to a stop and will not go on. The block that used to be a loop is now the corner and back.
Heavy, open-mouth breathing at restHe pants hard lying still, long after the walk or the heat is over, and his chest keeps heaving.
Fast breathing while he sleepsYou catch yourself with a hand on his ribs, counting his breaths, then counting again.
A cough after lying down, or at 2 a.m.The dry cough you hear from your bed and tell yourself was nothing.
Nights he can’t settleHe shifts, gets up, lies down again and the breathing never quite settles. You are awake too.
Unsteady on his feetLegs that sway or give way, most often after the doorbell or the leash. For some dogs, a faint.
Less play, more sleepThe ball stays in the basket and he sleeps through the afternoon he used to spend at the door.
Recognized two or more? You are not imagining it. His heart needs support, starting tonight, and it starts with his next dinner.
WHY IT HAPPENS
The heart that never gets a day off
Even asleep he is not off duty. His heart is beating through every minute of the night you spend listening to him breathe.
A human heart turns over about 6 kg of ATP, the cell’s energy currency, every single day [5]. In people, heart muscle cells are among the most mitochondria-packed cells in the body. Mitochondria, the energy plants of the cell, make the bulk of the heart’s ATP [6].
Those energy plants run on a helper molecule called NAD+. In people, NAD+ is widely reported to fall with age, though researchers still argue about how universal that is [7]. In a mouse study, the hearts of old female mice (15 months) held less NAD+ than the hearts of young ones (3 months) [8].
They lean on CoQ10 too. In people, CoQ10 is found at its highest levels in the heart, the kidney and the liver, among the tissues measured [9]. Also in people, ubiquinone, the body’s CoQ, peaks around age 20 in five of the seven organs studied, the heart among them, and then keeps falling as the years go on [10].
The pipes age too. In old mice, eight weeks of NMN in their drinking water restored the blood vessels’ ability to relax and eased the stiffness of the aorta [11].
Put it together and you get the walk you know: the same heart, the same job on every step, and less energy to pay for it. Think of a phone that is already in the red by lunchtime. It still runs everything. It just has less to run it on, and it needs charging sooner.
An illustration of the idea above. NAD+ decline is reported in people [7] and in aging mice [8]; ubiquinone (CoQ) decline with age is reported in people [10].
This is not a mystery. It is an energy-supply question, and an energy supply is something you can support every single day.
Why shorter walks, rest and waiting haven’t been enough
If you have tried most of these and the nights are still long, that is not on you. You did the caring thing every time.
Shorter walks and more rest
Kind, and sensible, but it narrows his world to fit the problem. It does nothing for the energy his heart cells run on.
“It’s just old age”
The sentence every owner hears and repeats. It names the age, not the cause, and it leaves you with nothing to do tonight.
Waiting for the next checkup
Checkups matter, but a year is a long time to watch the walk get shorter and the nights get longer, with nothing in his bowl built to support his heart’s energy supply.
A senior multivitamin or fish oil on its own
General support for the whole dog. Not built around the energy plants of heart cells.
They work around the problem. None of them is built to support the energy supply of his heart cells.
THIS IS EXACTLY WHERE PAWPRINT PROTOCOL STARTS
Pawprint Protocol: the daily dropper for the heart that never gets a day off
Seen your dog in these signs? This is the daily step you can take tonight.
Daily support for the aging heart’s cellular energy and healthy circulation, in a liposomal liquid on the dinner he already eats, with NMN (the precursor the body turns into NAD+), NAD+, resveratrol and CoQ10.
Heart-cell energy: NAD+ and CoQ10 are molecules the heart’s energy plants run on, and NMN is the precursor the body turns into NAD+.
Healthy circulation: resveratrol, a plant compound studied for its effect on the blood-vessel lining, rounds out the four actives.
Easy, every day: a dropper on the dinner he already eats, with the dose set by his weight.
Liposomal: built to be absorbed, not just swallowed.
What owners watch for: longer walks, more play, calmer nights.
Nothing to chew and nothing to push down his throat. Add the daily dropper dose to the food he already eats (best with wet food or kibble) or give it by mouth. The dose follows his weight, from 1 to 4 droppers a day.
Four actives, one liquid: what each is there to do
1
NMN
The lead active. The body turns NMN into NAD+, the helper molecule heart-cell energy plants run on. In elderly mice, the NAD+ booster NMN improved blood flow and endurance by increasing the density of the tiny blood vessels, the capillaries, in leg muscle [12].
2
NAD+
The helper molecule heart cells run on. Pawprint Protocol includes it directly, alongside NMN, the precursor the body turns into it.
3
CoQ10
One of the molecules the heart’s energy plants run on.
4
Resveratrol
A plant compound studied for its effect on the blood-vessel lining [13].
Dogs and their people, shared by Pawprint Protocol creators.
Dropper bottle in hand, Rottweiler at her side
Bowl down at dinner time
Dropper over the bowl, then dinner
What customers wrote about Pawprint Lab: walks, energy and play
Excerpts from public Trustpilot reviews of Pawprint Lab; cuts are marked with …
NW
Nancy WellsUS
July 9, 2026
… Beau is 7 and was already slowing down, having trouble getting up, and gaining weight. … We are headed into month 3 and today he brought me his Frisbee for the first time in over a year and jumped for it. …
Trustpilot review of Pawprint Lab
SH
Simone H.US
August 7, 2026
I started using Pawprint Liquid supplement for my 11-year-old Mini Schnauzer a little over two months ago, and I’m so glad I did. … Since she’s been taking Pawprint her vitality has returned, and she’s active again. I can truly notice a difference. …
Trustpilot review of Pawprint Lab
CP
Chris PriceUS
June 21, 2026
… I know this product helps my 14 yr old dog tremendously. …
Trusted by 100,000+ customers across Pawprint Lab · 90-day money-back guarantee
WHAT TO EXPECT
What your first 90 days can look like
Pawprint recommends at least 3 months of daily dinners, and the 90-day guarantee covers every one of them. Keep a short note of his walks and his nights from the first dinner, so you are comparing against your own notes and not your memory of a bad night.
What owners watch for: longer walks, more play, calmer nights.
1
TONIGHT
Make it part of dinner
Dose by weight, 1 to 4 droppers on the food he already eats, same time every day.
On his usual meal
Same time every day
Write down tonight’s walk and night
2
THE FIRST WEEKS
Keep a line a day
A line a day: how far the walk went, how the night went, whether the ball came out of the basket.
The corner or the block
The stairs
The ball
3
AROUND DAY 30
A month in: read your notes
Read your notes side by side: the walks, the nights, the stairs.
Keep the routine going
Compare walks and nights
Let the next bottle arrive on schedule with Subscribe & Save
4
BY DAY 90
Give it the full three months
Pawprint recommends at least 3 months of daily dinners. The 90-day money-back guarantee covers website orders: email us within 90 days of delivery.
A full three months
A clear view from your notes
Keep going, or email us
His heart will take tonight’s beats either way. His next dinner can be the first dose.
We recommend three months of dinners, so we back all three. Try it on his dinner, keep your notes on his walks and his nights, and if it is not right for him, email us within 90 days of delivery for your money back.
1Order on pawprintlab.com and give it to him daily with his dinner.
2Walk him, watch his nights, keep your notes.
3If it is not right for your dog, email us within 90 days of delivery for your money back.
The 90-day money-back guarantee applies to orders placed on pawprintlab.com.
“Old age” names his birthday, not the cause. Coughing, breathing that has gone fast or heavy and tiring on exercise are among the signs a heart in trouble gets named for [1][2], and in most dogs with mitral valve disease the murmur is first heard years before any sign of heart failure shows [2]. A heart that has beaten all his life runs on energy like any muscle, and Pawprint Protocol is daily support for that energy supply: the cellular energy his heart runs on, and healthy circulation.
How fast will I notice something?
Give it the full three months, the way Pawprint recommends, and keep a short note of his walks and his nights from day one. Read it around day 30, and again at day 90 while the 90-day money-back guarantee is still open.
Can he take it with his heart medicine?
Pawprint Protocol goes on his food as a daily dropper, and the label lists what is in it. Bring the bottle to his next checkup so his vet can see exactly what he is getting.
How do I give it to a tired or picky dog?
Mix it with food (best with wet food or kibble), or give it directly by mouth, at the same calm time each day. Dinner is the easiest anchor: a routine he already knows, with nothing to chew and nothing new to learn.
How much do I give?
Daily, on food, by weight. How long a bottle lasts depends on your dog’s weight; the product page shows current directions.
Dog weight
Daily dose
Under 22 lb (under 10 kg)
1 dropper a day
22-55 lb (10-25 kg)
2 droppers a day
55-88 lb (25-40 kg)
3 droppers a day
88+ lb (40+ kg)
4 droppers a day
How long does a bottle last?
That depends on his weight, because the daily dose runs from 1 to 4 droppers. The product page shows current directions and delivery options, including delivery every 4 weeks.
What is in it, and what does liposomal mean?
Four actives: NMN, NAD+, resveratrol and CoQ10, in one liquid. Liposomal means the ingredients are carried in liposomes, tiny bubbles made from fats; Pawprint Protocol is built to be absorbed, not just swallowed. Other ingredients: Vegetable Glycerin, Purified Water, Rice Syrup, Beef and Apple Flavoring.
Has NMN been studied for safety in dogs?
Pawprint Protocol is made for dogs, dosed by weight, made in the USA with domestic and imported ingredients and third-party lab tested. Oral NMN has been through a subacute toxicity study that dosed beagles and found it well tolerated [14].
How does Subscribe & Save work, and can I cancel?
Save 25% when you subscribe, with free shipping. The product page shows delivery every 4 weeks. You can pause, update or cancel anytime in your account or by contacting support. Prefer no subscription? There is a one-time option on the same page.
What if it is not right for my dog?
Email us within 90 days of delivery and the 90-day money-back guarantee applies to orders placed on pawprintlab.com.
Where is it made, and how fast does it ship?
Made in the USA with domestic and imported ingredients, and third-party lab tested. Pawprint Protocol ships from a US warehouse; the product page shows current delivery timing.
His heart has never taken a day off. Start tonight: his next dinner can be the first dose.
The walks, the nights, the hand on his ribs. He is still here, and so is tonight’s dinner. Give his heart its daily support starting now.
[2] Keene BW, et al. ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs. J Vet Intern Med. 2019;33:1127-1140. doi 10.1111/jvim.15488. PMID 30974015. Dogs.
[3] Rishniw M, et al. Sleeping respiratory rates in apparently healthy adult dogs. Res Vet Sci. 2012;93:965-969. doi 10.1016/j.rvsc.2011.12.014. PMID 22240295. Dogs (114 healthy dogs).
[4] Chetboul V, et al. Resting heart and respiratory rates in dogs in their natural environment (AI-COLLAR). Front Vet Sci. 2025;12:1667355. doi 10.3389/fvets.2025.1667355. PMID 41030684. Dogs (703 apparently healthy dogs; the lifetime total is an estimate derived from the published median resting rates).
[5] Watson WD, et al. A mitochondrial basis for heart failure progression. Cardiovasc Drugs Ther. 2024;38:1161-1171. doi 10.1007/s10557-024-07582-0. PMID 38878138. Review (human heart).
[6] Murphy E, et al. Mitochondrial function, biology, and role in disease: a scientific statement from the American Heart Association. Circ Res. 2016;118:1960-1991. doi 10.1161/RES.0000000000000104. PMID 27126807. Review (mammalian heart muscle cells).
[7] Peluso A, et al. Age-dependent decline of NAD+: universal truth or confounded consensus? Nutrients. 2022;14(1):101. doi 10.3390/nu14010101. PMID 35010977. Review (several species, including people).
[8] Carpenter BJ, et al. NAD+ controls circadian rhythmicity during cardiac aging. Commun Biol. 2026;9:476. doi 10.1038/s42003-026-09818-1. PMID 41813966. Mice (female, 3 and 15 months).
[9] Aberg F, et al. Distribution and redox state of ubiquinones in rat and human tissues. Arch Biochem Biophys. 1992;295:230-234. doi 10.1016/0003-9861(92)90511-T. PMID 1586151. Rats and people (tissue measurements).
[10] Kalen A, et al. Age-related changes in the lipid compositions of rat and human tissues. Lipids. 1989;24:579-584. doi 10.1007/BF02535072. PMID 2779364. Rats and people (tissue measurements).
[11] de Picciotto NE, et al. Nicotinamide mononucleotide supplementation reverses vascular dysfunction and oxidative stress with aging in mice. Aging Cell. 2016;15:522-530. PMID 26970090. Mice (male, 26-28 months).
[12] Das A, et al. Impairment of an endothelial NAD+-H2S signaling network is a reversible cause of vascular aging. Cell. 2018;173:74-89. PMID 29570999. Mice. Erratum: Cell. 2019;176:944-945.
[13] Li H, et al. Resveratrol and vascular function. Int J Mol Sci. 2019;20:2155. PMID 31052341. Review (cultured cells and rodents).
[14] You Y, et al. Subacute toxicity study of nicotinamide mononucleotide via oral administration. Front Pharmacol. 2020;11:604404. doi 10.3389/fphar.2020.604404. PMID 33384603. Beagles (a safety study); the NAD+ readings in that paper came from mice, not the beagles.
Each study above is labelled with the species it studied.
Disclaimer
THIS IS AN ADVERTORIAL AND NOT AN ACTUAL NEWS ARTICLE, BLOG, OR CONSUMER PROTECTION UPDATE
This is an advertisement for Pawprint Lab™ and is intended for informational purposes only. All information provided by Pawprint Lab™ does not constitute medical advice and should not be used as a replacement for veterinarian advice. Please consult your veterinarian regarding any change in treatment or supplementation.
Individual results may vary. The research cited on this page studied the individual ingredients, not Pawprint Protocol, and results may differ in dogs.
Please note that Pawprint Lab™ products are not drugs and are not intended to treat, prevent, or cure any disease.
Pawprint Protocol is a dietary supplement, not a medicine. It is not intended to diagnose, treat, cure or prevent any disease, including heart disease. If your dog coughs, tires easily, breathes fast at rest or faints, see your veterinarian.
The video clips under the headline and in the sections “7 signs his heart is working harder than it should, the ones owners write off as “just old age””, “The heart that never gets a day off”, “Why shorter walks, rest and waiting haven’t been enough” and “His heart has never taken a day off. Start tonight: his next dinner can be the first dose.” are real footage of other dogs, shown to illustrate the signs described. Those dogs are not Pawprint customers, and the clips are not product results. Three photos in the sign list are illustrations.
The photo and videos in the reviews section come from Pawprint Protocol creator content; the dogs shown are not the reviewers quoted.
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